cheating!

Been with my ex fiancé for 4 years and i caught him cheating! AND he got the girl pregnant (please do not judge me, I know you'll be harsh because I stayed) we fell apart and things came back together I gave him a second shot! Planned our wedding etc now I just found out he's been cheating with the same person! And my heart has shattered and I'm completely done with him! Since I have caught him cheating again he's been distance, we have a 1 yr old together and he hasn't seen LO and I been providing for LO on my own. I've asked for diapers and other things and we haven't gotten any. I would like to apply for full custody since he's clearly been showing he doesn't want to be a father. LO is on the urge of bring terminated from insurance, i do not work since I had a still born and I'm slowly getting back up. I've asked for copies of pay stubs just so they can keep on her insurance and I never gotten an answer from him.