How can i make my sons mom know i made a mistake in leaving her? Advice?

Im 29 and have been in a relationship with my fiancee for 8 years and have been engaged for 3yrs, she is 26. I am a firefighter and work shift hours and she has a full time job we also have a 6mth old son together. I wanted to become a father for years and i adore him. My ex & i haven't been getting on that great since the birth of our son, She comes from a large very dysfunctional family who are alcoholic's but also work on the job, Many of her family can't keep a relationship or a marriage as they have all either left their partners or cheated on them. She was really rebellious when i met her but she tries so hard to be the opposite of her family and worked really hard to get her career. Im in love with her so much but i couldn't stand the fighting and tension anymore, I've asked her to try counseling but she says we don't have the money and we don't need a third person sticking their nose in that we can work on this together. She is like her family and can be very stubborn and really hot headed, we have had arguments a lot and then she would break down crying saying she can't take this anymore and i try so hard to cheer her up. I play in a band sometimes and i dedicate songs to her and if she is pissed at me i always play her an angry song i wrote then she turns on me or walks out. Two weeks ago at the firehouse i asked her to drop me in something i forgot and she brought the wrong thing and i told her she either had a 2 second memory/brain the size of a fish and she pushed me & told me to f*ck myself and left even, i tried to call her back. We broke up the next day as i thought it would be a wake up call for her but now she wont even speak to me and she moved out of our house to her brothers place, she gets someone else to drop my son over to me. I love her with all i am & i can't imagine life without her this all backfired on me, I need some opinions on what to do!?