Healthy Relationships Support Group
No relationship is perfect. A long-term relationship requires constant effort to understand each other, fix misunderstandings, solve problems and continue to grow as both individuals change and evolve. How we deal with our misunderstandings is the focus of this community. Join us to find support, get advice, and share your experience with your relationship.

and yes, he will likely get over it in time.
You were honest
. If he can't except what you did before you ever knew him he needs to get out of the relationship now, not punish you and make you feel flawed in some way.
Is he a very serous bf ?
He is a very serious boyfriend, which is why it's even harder. I'm not sure if he has been cheated on in the past. But what he's doing probably has to do with something that happened at the beginning of our relationship...
When we were first seeing each other, we verbally agreed that it was okay for us to be seeing other people. I was still getting over a really tough breakup and was not ready for a new commitment. Later on, when we got more serious and decided to commit to be mutually exclusive, he asked if I had actually been seeing other people. When I honestly told him that yes, I had, he got really upset. I feel that he is still holding that against me. I can understand why he's upset, but we talked about it! It's not like I just "assumed" it was okay or anything...anyway so I feel like I still represent "that" kind of girl in his head, and now he still can't trust me.
His issues will make your life miserable
i agree that you should let him go. he is not at the age or that stage in life where he is fully capable of grasping the concept that that was then n this is now.
he basically told you that you cannot be trusted... his idea of you is flawed ...its his problem... not yours...
however... he is also being honest when hes telling you how he feels about it... wrong or not... that's his reaction.. he really needs time to work it out...
let him know you need his help in working through this with him...his reaction should give you a heads up as to his ability to support you as a partner in the future...
another thought that has not been mentioned... is he may be using this as a tool to try and control you... please don't get caught off guard...