I'm afraid I don't know enough about what your life was like with him, so I probably don't know how to respond to this. So, rather than try give advice, come up with some clever response, or fall back on some empty platitude, this gesture will have to do for now.
If I were to give any advice, it would be, just be patient with yourself and accept your feelings as they come, without shame or blame. Like I said, I don't really know much about the situation, but it sounds like you're grieving, and there's no set time frame on that. Sadly, there's no way around it, only through it. But you may be surprised by what's on the other side.
I'm glad I came across your post, because it's a good reminder to me that I'm not the only one who is hurting and missing someone.
Kat, aren't you idealizing the past? You were unhappy with him which is why you left him. Leave him in the past where he belongs and look ahead. You deserve so much more than he gave you.
@SmartKat You just be you. That is who you are. No pretending. No hiding. And you know unless you change how you think about the past, you will never leave it behind and move forward. Those are facts, Kat.
@SmartKat But you don't live in the past now. You live in the present. It is a gift. You work toward the future you want. What about your college years was so great? Perhaps you can concentrate on getting that feeling again? If you drive by looking always in the rearview mirror, you shall crash.
@SmartKat Even if you may be helping someone or some others? You are the only person I know who is unhappy after leaving an unhappy relationship. But, also, you are the only one who looks backward instead of forward, Kat.