I feel like my gf is losing love for me

I don't know what to do anymore I love my gf she is the mother of my child we have been together for more than 5 years and it feels like everything is going down the drain I have never cheated on her and never will i just don't know what to do anymore we constantly argue and it keeps getting worse before it wasn't really bad but she has always been verbally abusive towards me constantly calling me a bitch saying fuck you fuck off and so on at first I would just be sad depressed and I would even cry when she gets like that after the argument she would act like everything is fine and once in a while she would apologize I do have my share of problems but not for to treat me like that as time has passed I have become more defensive against her when she acts like this and I hate that I have become like this bcuz I dont wanna treat her bad or hurt her it has gotten to the point where I have called her a bitch about 3 times those occasions I have regretted and apologized to her and even tell her fuck you fuck off and it hurts bcuz I dont wanna be that guy who treats the girl he loves like shit I feel lost I don't want to be this person I dont wanna treat her like shit but I don't know what to do I have become worst towards her when we argue and I hate it we have a1 year old son and I don't want him growing up hearing us like that or with separated parents she says she loves but sometimes I don't believe it bcuz as bad as I have been with her in the most recent arguments she has been worse constantly telling me she doesn't love me that she loves someone else that she doesn't care about me and than 5 minutes after she says those things she tells me she loves me I just don't know what to think or do anymore I love her with all my heart I have given up so much for her I feel the need to vent out but I have no one to vent out to I need advice bcuz I am becoming worse with these arguments instead of stopping them or trying to stop them I make them worse by using the same tone and cussing at her and it breaks my heart bcuz she is going to leave me I'm scared to lose her I can't imagine myself with anyone else