I’m sorry you’re so upset.
It must really feel like your boyfriend cheated on you. The underlying problem is that you had a break up for eight months, and when you break up with someone, what they do is their business. You’re both free agents when you’re broken up. So, the reality is that he didn’t do anything wrong. Your disappointment is that he didn’t lose his virginity with you — he lost it with someone else. 😳 That’s a big deal and you’re not over that.
It sounds like after you got back together with him, you gave your virginity to him, and now you regret that decision — it may not have been the right decision for you since your virginity was a really big deal, and you were angry at him for sleeping with someone else before you. Nonetheless, you’re living with that secondary issue on top of his having slept with someone else during the breakup. I don’t think you’re over those two disappointments. Also, you didn’t really talk about what caused the eight month break up or whether those issues got resolved prior to your getting back together, or why you got back together again — but it sounds like there are some unresolved issues that are going to be thorns in the side of this relationship, until you work through them.
This is all a lot of emotional work — and it’s painful — but it’s important to understand that when you broke up, what he did was okay because it was his choice outside of your relationship, and that your giving him your virginity may have been a knee jerk reaction or a desperate move, but it wasn’t right for you. I think that this one-two punch may be too much for you to get over and this relationship may be headed for a breakup unless you can process what happened and why.