I'm sorry, your situation is harder than I thought initially.
Elena Nikolova wrote:He told me that I am flattering him with my jealousy. It is hard for understanding. To me, jealousy has more negative, than positive side. It is often irrational and risky for the relationship. Too deep and strong to be treated like a harmless spice, or to use it for raising self-esteem.
Jealousy, when not seen by the other part as exaggerated, can be a healthy aspect of the relationship. You seem to be very self-aware of your own behavior. So your jealousy is probably not being expressed in an exaggerated way, thus seems to accepted by him. He may have seen it as reinforcement of your feelings towards him. Maybe it also raised his self-esteem, as you suggest, in case it is very low.
In my current relationship, because I hardly ever express jealousy, when she thinks I am feeling jealous about some small thing, such as her dress, she opens a huge smile.

Years ago she would cry stating that I was never jealous of her, but now she understands that I am not a jealous guy, that I don't express myself like she does, and that I trust her.
Did he see you crying and loosing your sleep? If he did not, then he might be unaware of how painful it is for you. If he did, then he is probably does not care (from what you wrote it does not seem like he has changed anything in his behavior).
If I see my partner very angry accusing and devaluing me, I just get angry too. But if I see her crying quiet, I feel like crying too and I feel sorry for whatever I have done that may have sent her to that state, even if it was something normal.
Elena Nikolova wrote:Anyway, as you said, I will not take quick conclusions. I love him very much and I really want to continue with him. But I am still very insecure and confused.
I see you have good reasons to feel insecure and confused, due to this very suspicious way he is behaving.
According to my boyfriend, he was not informed about the other one.
In such case, he would be innocent and she would be the one lying. But you said he lies to you, so he can't be that innocent. It would be much more convincing if he admitted fault sometimes.
Sometimes he even lies me, that he is tired or have another job, to avoid meeting with me, because he already had planned to see her at the same time. (...) When I saw her photos, he told me he would give me access to all his online resources, in order to assure me that he haven’t done anything wrong. Then he quickly wiped completely and irrevocably all his chats with this woman, to prevent me from seeing them.
That proves his word is unreliable.
He even does not inform me before these meetings. He tells me later. For example, "I met with X, she complained that her boyfriend does not want to have sex with her. She was very upset," etc.
I do not consider my current partner too jealous regarding other girls. At least she is way less than my ex-wife. However, if I did something like this, I would probably get an immediate slap on the face.
I asked him how would he feels like, if I have secret meetings with some of my former lovers, in order to complain them of my irregular sex life.
I would try to hide my angry feelings pretending that I was not offended and test him with some question to extract more information from him like: "Poor guy, Does she know how good that your erection is?"
The opposite of the situation he described would be a ex former lover of yours complaining to you about his sex life. It would be a good idea to
pretend some situation like that. Just to help him to feel how it is to be on your shoes for a moment. Just need to make sure you don't make him insecure.
Once my ex had left me and was treating me terribly bad by phone, day after day, and not contacting me, etc. So I met her in the building's hall stating I had something to tell her, and said this:
"I have been very lonely, I miss you in my bed, I think you don't care for me as you did before and I don't know what is going on or what are your intentions. I don't know if you want to meed someone else, as you have done in past, yet I don't want to put you against a wall or to insist in having answers. After all, you are the owner of your life. And so am I."
Then I wrote "IIAF" in a blurry mirror with my fingers, and continued:
"Pay attention to this letters IIAF. They will explain everything I'll tell you now from now on. Ok? Well, something happened with me. After some time away from you, I had to find someone to talk to. Someone sensible enough to understand me. And I found, a female friend. I was very sad, depressed, and she heard me, understood me, cared for me, etc. We went to the beach, with friends, and later she invited me to her place. I got to know her parents and they liked me. Very nice family, in which I felt comforted. She has a very gorgeous body but is single. So once I felt like touching her and kissing. We got close, but I stepped back. Because I didn't feel it was right to start a relationship with her since you and I had not officially broken up yet. So I have been thinking about her, but also about you, because I love you, but I'm more attracted to her than I ever remember being. So I because I feeling confused, now knowing what to do, I choose to come by, tell you my reasons and break up now. I'm sorry, but I need to be happy."
At this point she was all in tears. Her rejection feelings dissolved. So I said:
"Now relax let me tell you one thing. Remember that letters I wrote, IIAF, I'll now tell you what do they mean. Guess what."
She said: "They are the initials of her name?"
"No. This story I told you was just to help you to remember something you seem to have forgotten. The feelings you have for me and how important I am for you. The IIAF letters that describe everything I said mean IT IS ALL FAKE. I have not met anyone. Not at all. Yet it is true that I miss you and I want to be with you."
Because I was an excellent actor, she fully believed me while I was faking it and really felt how would it be for her if I did that. She actually took some time to believe it was all fake. So the trick worked. Many years went by and she never again pushed me away.
If they both are only friends, what is the problem sometimes to "drink coffee" the three of us together? Apparently, there is something more between them and they try to keep it hided from me.
My partner was having some slightly suspicious conversations with a guy from her university. I never repressed her. But a given day I went there without notice to pick her out. Got to know her friends and could observe that she was very comfortable but he, on the contrary, became serious and nervous. They never again talked to each other. He changed his university campus to a far place. So my conclusion, based on everything I know about her, was that although there was an attraction between them, she did not have any intention of cheating on me, but he did have intentions of the kind, like pulling her away from me.
I really want to stay with him, but If he continues with this behavior, I would consider to leave him.
Chances are he will continue with this behavior.
It will hurt very much, but it is worse for me to see how my cherished beliefs about him and our relationship proved to be illusions.
Oh yeah, that's the worst part. Disillusions...
After all the conversation we had, I hope he understood the risk. It depends on him whether he will be able to keep me in the future.
Unfortunately risks are not very useful to be just understood when they are not felt. For instance I am very risk taking, because I like the adrenaline and I'm fearless. Sometimes I purposely choose the most risky path and only back up after things are so bad that I'm truly afraid. I'm thinking about sports, but it also applies to relationships.
If right after your most angry day you had remained in that state and all kind of contact with him for a short period, maybe just a couple of days, then he would be able to feel the risk. This may sound like manipulative silent treatment, but it is not if driven by genuine feelings. Just wanted to give you an example of how it can be helpful to express your negative feelings too, sometimes.
Do you have a reasonable explanation for his actions after I told you in detail about the specific case?
No, sorry. I can't say if he is having an affair and finds it exiting to do it secretly or if they are just close friends and he hides because you get anxious and press him. Anyway, if he is lying to you then that should be an important relationship for him. It is very good that you allow him to have his freedom, but for that to work he would to be transparent with you. Right the opposite of what he is doing.
Did any of your previous girlfriends knew about the naked pictures of your ex?
My current partner knew. I choose to be 100% honest with her, so years ago I told her about it. She was happy to know and asked to see the pictures and insisted a bit. I didn't show her any naked picture because this would be disrespectful with the ex, but I showed her some of the not-naked pictures. I regret that because it fueled her "benchmarking" tendencies. She said she was not comfortable with me having those pictures, and asked me to delete. I refused, because I did not open myself with her to be reprehended, but I did understand her insecurity. So I told her I would put them aside, that she should not worry because she was the best (and it's true) and all I would ask her was to have pictures of her so I could watch while she was not at home and remember her best angles. So she trusted me and through the years has given me so many good pictures. She likes to know that I look at those pictures when things go wrong between us.
By that time I didn't know she suffered from BPD and our relationship would be so hard. But other girls are not what we have trouble with it. One of the things she most admires in me is my honesty. And the music she chose to represent our relationships is "Billy Joel - Honesty" (
link)
Being honest does not mean necessarily to be loyal. It means that I won't plan things on her back and if something unplanned happens then I will let her know right after. She fully understands what it is to act on an impulse because she is so impulsive. We've had dates during break up periods but never cheated on each other.