Heather,
Just a thought..when I had obsessive behavior with my exAH (what is he thinking, what is he doing, etc.) I practiced the "Let go and let God" thinking every time I had one of those thoughts until it finally worked. I thought to myself, "how amazing, the brain is a strange thing". Personally, I had to remove myself from the chaos...we had no children together, had been together 4 1/2 years (1 1/2 married).. because (for me) once the trust was gone, the love was gone and I was not a big enough person to forgive and forget and needed the peace and serenity I achieved away from the situation. I am sure, if we had children together, I would have chosen a different path and I admire those who take it.
My point is (believe it or not, there is one in this rambling!) that you are an intelligent, beautiful young woman and have your whole life ahead of you. Do you really need the stress and chaotic relationship you are putting yourself through with this abf?? It's your decision and hard right now, but the important thing is YOU...put all this energy there! All said with love.
Hugs,
Susie