How can I recover from a massive lie to my partner

From a very early age, I've been a compulsive liar. At first, I would lie about small things as an act of self preservation. I would tell my parents that I'd done chores when I hadn't or would tell classmates that I had scored better on tests than I actually had. Furthermore, my affinity with lying was fueled by the fact that I was really good at it. I felt like I was getting away with it all the time and only ever lied in circumstances in which i knew I wouldn't be caught.

However, I started college this year and my views on lying started to change. I'm currently six months into my first relationship and this guy is like a dream. Our relationship is far from perfect but I feel as though he's the first person in my entire life that made me feel truly comfortable showing my true self. However, I did not truly start feeling this way until about two months ago. In the beginning, I treated this relationship as I would any other; I lied. I would lie about small parts of myself that I wanted to hide so that he would like me more and think more highly of me. And I told one particular lie that has ballooned into a bigger lie and I feel awful about it. Here's the lie:

In the beginning when he'd asked about past partners/crushes, I'd told him about a high school crush I'd had for years on a guy I will call M. I told M that I liked him and M treated me poorly/ignored me for about two weeks. After that M and I slowly began to become friends again and ended high school on good terms. However, in the beginning, my current boyfriend clearly had some feelings of jealousy towards M, so I came up with a lie on the spot and told him that I'd called M on my own time and told him that I didn't want our friendship to affect my current relationship. However, in reality, this never happened and M and I kept texting occasionally.

My current boyfriend confronted me about this a month or so ago and told me that I was being disrespectful in going behind his back and continuing talking to M. All this time, I have not had feelings for M, but have kept talking to him because he has continued reaching out to me. After my boyfriend confronted me, I finally did call M and set up a boundary so that he would not continue reaching out to me and so that my friendship with M would not affect my relationship with my boyfriend.

So as of right now, the situation is at a place where I could likely leave it and forget about it and leave it in the past. However, I'm currently at a place in my relationship where I'm tired of the ways this lie has built up. what felt like a small lie in the beginning ballooned into a much larger lie in the end that caused pain, jealousy, and confrontation. I then had to make many other lies to cover my tracks. Over these last few months, I've opened up to my boyfriend about several things that I was dishonest about in the beginning and most everything has been ok. I feel an immense internal pressure to come clean and confess this lie to my boyfriend but I know it will be very hurtful to him and I know he will need time to forgive me for lying and continuing this lie to such an extent. So my question is: what do I do??? Do I need to confess this to him or is it ok if I let it slide under the rug and commit to a future with him where I am honest and work on being more truthful? I just feel so stuck and frustrated and angry with myself for doing something so hurtful.

Please help
-J

Hey there, I don't know if you've already dealt with this but I'd say the best is just to come clean, if it's heavy on your conscience now, it will be later on as well and it is more likely that he'll accept it as a small thing for now... I also have had problems in my relationship because of my lies and I think the best is to just come clean...