Should I Stay With Him Or Leave ?

Okay so I'm 16 and pregnant. (Please don't judge my age I love my son to death) but anyway me and the father are really going through some problems. A girl texted me the other day and told me they had sex three times and of course it was really hurtful but we do have a baby coming in a couple months and I really want my baby to grow up with his parents together because I didn't have that 😔. But even after I found out he apologized, begged me to take him back, and said he wouldn't talk to her anymore , and he also bought me a promise ring. But I found out that he is still talking to her and he said he think he loves her and I really don't know what to do , all I keep thinking about is our son. Should I keep trying or just give up ?