should i stay or should i go?

Alright well heres the story. ive been with my boyfriend for 4 years now, weve had quite a up and down relationship. We also have a 1 year old son. once in our relationship i caught him talking to my so used to be best friend, telling her he had feeling for her and what not. (whole different story) we talked about it i decided to forgive him and we moved past it. we now live together after i got pregnant we decided to move to our hometown. so now we have been fighting constantly about little things, and sometimes big things. he does this thing that instead of talking to me he ignores me and mumbles under his breath just to piss me off more. he does this ALOT. Im really getting so tired of it. i love him i really do. and i want us to work out for our son. my parents split when i was younger and i felt like i needed my dad in my life more and i just sont want my son to go through all that. im trying but he just keeps doing things to push my buttons and we keep arguing, he also likes to put his family first even over me. he rather go out and spend time with his brother than me and our son. everytime we talk about it he swears he'll change that he will change because he loves me and blah blah blah. honestly im getting tired of listening to his same story. and weve been thru so much already, im just tired i dont know what to do. HELP.