Thank you for being brave and sharing your feelings. I think the first thing you need to do is separate your fantasies and desires from your frustration with your sexual relationships with others (or lack thereof). Your fantasies in and of themselves are not harmful, nor are they shameful, "weird," disgusting, or in any way indicative of your being a bad or unworthy person. You have given no indication that you would harm anyone or desire to actually harm anyone, and as long as you separate the fantasy from the action, I see no reason why you need to feel badly about yourself for harboring those fantasies. A lot of people have the same fantasies you do and lead perfectly happy, healthy lives without hurting themselves or others.
The problem is that you're having a hard time opening up and trusting others, I'm guessing partly due to the negative experiences you describe having with past friends, etc. This is a problem because it causes you distress, which is troubling and definitely needs addressing, but from what you've said here there isn't any reason at all why you can't at some point have the kind of intimacy and trust with another person that you want. Have you thought about seeing a therapist who specializes in intimacy issues? I assure you, any therapist worth their salt will NOT be shocked by anything you've revealed here, and will have lots of advice for you about how to unravel your feelings about sexuality and intimacy with others and help you develop tools to deal with the problem and get to a better place emotionally. Cognitive-based therapy will direct you away from looking at the past to try to explain your issues, which may have nothing to do with how you were brought up or parented or anything like that, and instead focus on practical advice for what you can do NOW, in the moment, to start feeling better.
Again, I want to stress that the problem is NOT with your being "sick" or "perverted." I am married and have kids and have always had the kinds of thoughts you do and I can honestly say they don't negatively impact my life or relationships. I have zero desire to harm anyone and I enjoy the fantasies as one facet of my sexuality that gives me pleasure--desire takes many forms, and it needn't control you or determine whether or not you can have fulfilling relationships. Your fantasies do not determine your worth as a person or the quality of your moral character.
I hope you can reach out to someone who has experience dealing with intimacy issues and who will help you reach a point where you can both give and receive physical and emotional satisfaction from others in a way that makes you feel good about yourself, safe, and happy. There are so many others out there who share your situation. I wish you the best.