I have been going through this, too. I have the “always something there to remind me” problem. It’s been over a month since the breakup, so it is getting a little better.
I have been keeping busy by going to the gym (swimming laps is my equivalent to running, with the rhythm of the strokes and focusing on the breath); but I also enjoy the yoga classes.
I’ve also joined some social groups that go for walks and get together for various activities. This gets me out of the house and introduces me to new people and activities.
When the emotions get a bit too much, I write in my journal. If I’m unable to write at that moment, I will use logic to help ease my mind, because as much as it hurts, I know that it is his mistake and his loss.
Your circumstances may be different. If there are regrets and perhaps some guilt that you are troubled by, you may want to compose a letter to express that. But take your time – days or weeks even – to put it together, review, edit, analyze and revise. When something pops up in my head that I want to say or ask, I jot it down (I use the Notes app on the iPhone – very handy) then incorporate it into my letter (or journal entry).
Doing this seems to help me take a step back and examine the situation a bit more objectively. It has helped me recognize the things I did that contributed to the problems we had.
What nags at me in the middle of the night are those questions that only he can answer. Unresolved confusion and contradictions tend to eat away at me. So accepting that he probably doesn’t really know the answers himself is all I can do to comfort myself.
This relationship was a short one for me, but it was a life-changing experience. So I recognize that while I am sad that he gave up on us; I am a better person for having known and loved him.
I hope it helps you to know that you’re not alone, and that some if my suggestions will be beneficial to you. Hang in there.