<human>: Can you provide a brief overview of the text?

The boyfriend and I are both 20 and have been dating for four years; needless to say, it's not all roses and sunshine anymore.

I still have deep feelings for him, but I'm beginning to understand that the relationship is unhealthy: he does not respect nor establish boundaries around his exes or other women showing interest in him, and there is an ongoing emotional affair (which he refuses to acknowledge, ftr) between him and an ex.

Until he gets his priorities straight, I do not want a romantic relationship with him. But it's VERY difficult for me to imagine a life without him as I've spent 1/5th of my life with him by my side; I associate many memories and milestones with him, and he has made me into the better person that I am today.
I can see us happy if his ex is out of the picture and his circle of friends improves, because it was fine until she popped back into his life.
<bot>: How do I go about ending this relationship, but letting him know that I'm willing to try again if he reprioritizes?