My boyfriends job is taking a toll on our relationship..HELP!!?

Ok my boyfriend and I have been together 6yrs, and in the beginning everything was great. Then he excepted this job as a cop and i was able to put up with it for a while. Then in 2006 its like i started to feel like he was cheatin on me with his job (i know right) cause hes always at work. He works 2 jobs one from 7am-4pm and the other from 7pm-3am. I was able to deal with that, cuz he was still able to come c me. Then late 2007-2008 it went to 7am-4p and 6pm-3am, there wasnt really anytime for us. I even felt neglect and i told him how i felt, but things didnt change and i ended up cheating, but i told him and we worked through it. but things are still the same (im not gonna cheat again o no h*** no). but we have broke up because of it, but i realized i dont want n e body but him so i came back (less than 2mons later). In some ways i feel us goin down hill. but wen i do c him and/or hear his voice its like all my worries are gone..What should i do? I dont wanna leave. How can i get him to c where im coming from? How do i get him 2 make time for me? we are suppose to be gettin married so, in a way it makes things a lil better cuz then i'd c him more cuz we'd b livin together and he would have to come home..But i jus dont know