What do I do ?

So I live with my ex who was my best friend for 9 years . We both say we love each other but can't find a way to work things out to be together again everything just always leads to a fight and each fight gets worse well go for weeks without talking but then we'll make up and things will be great except the fact that we never actually solve anything or end up together somehow just in another fight. I love this man and want to work things out and be together he's absolutely amazing with my son... The bond they have melts my heart . My sons father isn't really around he comes and goes as he pleases. I just don't know what to do anymore. Let go, hold on to hope that he'll come around and want to talk things out and be together again. I just can't make sense how we went from best friends to strangers . 
How do I get through to him I need any advice everything I try has backfired on me ...