Should I fight for us or walk away

I don't know what to do.. I'm sorry if its long. I have know this guy for about 2 years we started talking through facebook one day he had always seen me around and one day he messaged me. We officially met in person because we had a mutual friend at the time about 1 year ago and have been together 10 months now exclusively. (Before I finish Ama clear this up I was involved with the mutual friend that I had known for 4 years. We never dated or anything we just had sex 3x I was in a bad place around that time so I didn't think my decisions through because I simply didn't care. It didn't mean anything and at the time I didn't see no harm because I never expected to fall for the guy (his friend) I have been with now they have been friends since they were kids & the guy told all their friends about the encounter which I only found out because my guy told me) Well me and my guy have been together & involved for 10 months now it feels longer because we have been through so much. I started liking him because he was nothing like anyone I've met. I didn't plan on anything going on I did everything to avoid it because they where friends and still are not as close but they are. My feelings grew he showed me the side of me I had forgotten was there. I was feeling happy again I wasn't looking down on myself I felt a sense of relief for the first time in a long time I was seeing my life more clear I started understanding that I was being myself I was acting out of hurt. He has a wonderful side he treats me well and is great with my son which has caused the feelings to grow much faster my son sees him and thinks he is his dad he has never had anyone else but me to be there for him. In the beginning I didn't know if it was just a fling or if it will be serious so I didn't want him around my child or build a relationship with my child because I didn't want them to get attached to then be hurt. I pushed away so hard because of the friend I had sex it didn't feel right but my feelings went on there own we had an instant connection. its so easy to open up to each other. At first it didn't bug him much about the friend because I never dated that guy but as time went on and his friends started noticing he was still around me they began to bring it up and he says he didn't care what they thought or said but it did get to him. He chose to stick around me and my son to be a part of us spending all the time we could together when he wasn't at work. But like anyone else we have differences, our arguments, disagreements, etc.. for the most part they aren't big but some do get big. I know its normal to argue and when two people have a difference in views its sometimes hard to get on the same note. Within everything we have been through one has been that I got pregnant but it didn't end up working out but we stood next to each other through it. The baby would've been born this very month, this is also the month that we have clashed so much I don't know if its the tension or what but its caused so many problems now we clash over almost everything. We have out great moments where we spend time together everything is perfect its like we are a family just us 3. We don't want to be apart or anything but then we have our days where we cant come to any understanding he only sees what he wants and I get very frustrated that I cant get threw and instead of giving him his space I push more I get scared of being hurt I push away and I feel lost at that moment. right now we got into a huge argument and it feels like there is no solution I don't know if to fight for us or give up. We got into it because he thought I was giving attitude to him since I wasn't talking I was just quiet listening but I was agitated. He tried walking away but I didn't want him to leave so I went after him and we where out front of his house we started arguing he had told me to stay in the car that he was going inside and for me to go home that we will talk later but I got stubborn and didn't listen I know I made a mistake for provoking a scene in front of his house. but I had only went because he asked me too I wanted to see him we hand really talked all day I missed him and didn't want him to walk inside mad. After that I came to found out that when I got home he was talking on the phone with another girl I didn't know who or what they talked about so I jumped to my conclusion of his mad at me n went to seek comfort in another female because why would you be on the phone with the opposite gender at 1am (yes I know its never goof to assume) later he came clean without me having to ask much. He was talking to a friend who he has know since they where kids because she is having problems with her guy who is also his friend n stuff he said he mentioned we fought but didn't talk about what exactly because it wasn't for her to know. I believe him because he has never given me a reason to doubt him or lied to me and has never hid anything from me. I just was mad and my focus was on what it looked like he asked me what I thought was going on I didn't lie and told him and he ended up taking it out of proportion now he thinks that I think he will get with her n get in between their relationship and walk away from us he wouldn't let me get a word in he just came to his own conclusion n said he was fed up with all this bs I tried telling him I know he wouldn't do that to his friend he isn't that guy that's actually his friends girl and they just had a kid. He started telling me about the guy I had sex with before him whom I don't talk to at all anymore because I didn't want anything to do with him or anyone else in that matter that wasn't my guy. He said that if I wanted him to look at me like if I was his friends lady and that he was disrespecting which I don't he knows because its not the same boat he got very angry and just clicked on me we haven't talked since I let him say everything he wanted to but he didn't allow me to talk from how mad he was I don't know what to do I don't want to walk away or give up I am falling in love with him with us with how he is with my son and the fact my son sees him as his dad and us as his parents I don't want to lose him but idk how to approach him without causing more issues I know he has strong feelings for me because he hasn't left my side or doubted me he has been there when I needed someone and he loves my son he loves being together he takes him on his own where they go out together n I get alone time. idk if to fight or walk away and call it quits idk if he is willing or not I don't want to lose him I don't wish to bring anyone else around my son its not that im sprung its just that I feel in my heart he is the right one and that we can get throught this but if I do fight for us idk what to do I know he is mad at me because he didn't like the idea of me being involved with another girl.. please help advice I feel lost right know and don't wish to make more problems I would love to fix it but don't know if possible...