That is definitely a very difficult situation to be in but if it helps, I agree it might be best for you to be apart right now. It sounds like there are a lot of unresolved concerns in his past as well and often we need to work through our own things before getting into a serious relationship.

All I can suggest is give it time. In time the pain lessens and you may be ready to try again, but do it in your own time. I would suggest staying connected with your therapist and DBT group as much as you can and maybe discuss it in therapy if you are comfortable doing so. Your T might be able to help you with strategies for managing and, in time, ways to start connecting with others again.

Also, try not to 'bury' the feelings if you can - it is ok to grieve the loss of the relationship and everything that came with it - all of those firsts. It is really hard to lose, but in time it does become easier again.