I read about your situation and its unbelievable how similar our situations are. And i think i might be able to help.
I know this might sound strange but i found my answer in meditation. I have an overactive imagination and I would have fantasies about how things could be between me and the guy in my life. Until one day, i realised that none of what i imagined manifested in real life. so i meditated to quiet my mind and minimise the fantasies. then i got to the root of the problem.
I asked myself "what does this guy represent to me?". The truth was he represented what i could have and what i've been looking for for a long time: a caring, giving partner. Realising he stands for something that i want, led me to realise why i was in denial. We were simply incompatible but i was addicted to the idea that i could finally have theguy who is as giving as i am.
Letting go of obsession needs a thorough investigation of why you want to make this work so badly. Yes, take care of yourself more but at some point, you're going to realise that you're only taking care of yourself so you can be better for him. The ego is a tricky thing. Think about him and your situation objectively. Then you'll see that what you're actually missing in your life is not him but something you need within.
hope it helps.