I was d and I don't know what to do?

Almost three months ago I was d. It took a while for me to come out with this information though, I first told my friend maybe a week after it happened. Then I told my boyfriend, which I wasn't planning on doing at the time. I was very confused about the situation. But he sensed something was different, he thought I cheated so I finally told him what happened and he still remained skeptical. Immediately after this I told my Mother and started seeing a therapist. The therapy has really helped. But my boyfriend has lost all trust for me which is now my main concern. It is true, and I admit that I was wrong because now I know I would not have been d had I not put myself into a situation where a was hanging out with a boy (not my boyfriend) by myself. Only being 18, I am very naive and I should have known better that guys don't just want to be friends, I curse myself because I should have been more wary. But I can't change the past and I have grown very much through what happened to me and learned so much these past few months. How can help my boyfriend cope? He is feeling many of the emotions of distress I felt and still feel but seems to be unable to come to terms with things. I know and understand that he feels betrayed, he feels like I am 'tainted.' How can I show him that our love can be stronger than ever? I have been doing all I need to show him he can trust me, this he admits himself but deep down he says he still feels like I cheated on him. This just bothers me so much because I love him and did not cheat on him, I was d. It's like he just doesn't believe it because the situation I put myself in, even though I had no intentions of having with this guy.