My mental illness is ruining my engagement

Since 7 years to my age now 21 I have a long list of mental history I've been diagnose with.. Bipolar, manic depression, borderline personaity disorder, Oppositional Defiant Disorder (ODD), and ADHD. Well I have my moments life is great then it seems like the world is against me and I can barely get out of bed just because I have no energy. And I hate winter time because that seems like when everything goes to shit and I hit rockbottom. Every relationship i've ever had things are wonderful till I start getting use to them then my episodes happen. My episodes when I was extreme younger all I wanted was attention and love from my mother and stepdad I started cutting first time I tried committing suicide I was 12 years old. At 16 I met the father of my child and it was wonderful but once I got use to him I started lashing out.. By lashing out I mean if you try and leave me I will hit you and just go insane while running around with a knife cutting myself (all before my son was born) 3 years ago I go really upset about a guy I had recently started dating after me and my child's father spilt. He broke up with me and I OD on over the counter medication and was hospitalized for 3 days because of the toxin levels in my body. DHR got involved and I cleaned my act up despite my mental problems I love my child I work a full time job full time college student my son has always had a home we live on our own in a beautiful apartment i pay my own bills no help no child support im very independent so before any nasty comments calling me a selfish mom. My child has never seen this side of me has never been around me during any suicide attempts he has never seen drugs beer etc I will not allow any people around my child when he is with me Monday-Friday it's me and him. Saturday-Sunday he goes to his dads. But back to everything I cleaned my act up then started dating another guy who was one of the unhealthiest relationships I've ever been in. So much cheating no respect if there is anything I regret it's allowing my child around this guy even though still nothing happen he had me in tears everyday and was a influence on me I started drinking heavy on the weekends no drugs just drinking. But i got so overwhelm with everything again I OD again and was found barely alive by friends of mine and then DHR came and took my baby but I could see him whenever I wanted at his fathers house supervised But i messed up again then a good friend of mine died after we just had his birthday party at my house the night before I was so depressed I just wanted to be happy so I got really drunk planning to wreck my car and die ran from the cops crashed into a tree took my baby for 6 months i won him back i did everything i was suppose to do and to this day im sober and i refuse to ever loose my precious son again As of right now I've been engaged for about 3 months to my best friend of 14 years And the love of my life he treats me so good I've never had anyone do things for me like he has. We have had past problems we are young and somewhat have got through them but constantly I'm thinking he is texting a girl seeing a girl lying to me and no evidence he gives me I refuse to believe it because he probably deleted it or is lying but deep deep down I know he probably isn't doing anything but my anxiety is so high I can't help but freak out. We will be in a fight and as soon as he grabs his keys to leave I snap it's like a trigger I hit him scratch him I get so mad I can't control myself I constantly worry what he is doing where he is who he is around well I had a major episode the other night and just blacked out I barely remember anything I tried hanging myself but he caught me in time. He has moved out until I get back on my medications and seek therapy. After that night he refused to talk or see me till I attempted to get help. I had a appointment at a behavioral health center on December 28 but he wanted it sooner so I moved it up to this coming Monday but it still didn't seem good enough I'm doing this for myself and from keeping my family from falling apart but since that night he barely talks to me he comes over late at night then leaves after a hour. I barely see him and when you have been with someone for 2 years always waking up next to them it's hard because he has been almost completely apart from me. Which makes my anxiety levels sky high I don't know what to do with myself all I'm thinking now is there is somebody else and he is only saying we are together so I won't hurt myself but plans on leaving me as soon as I get help. I can't loose him. I can't let my mental problems ruin such a good thing. I've begged him to just talk to me and see me and it's like he completely gave up on me and don't want to try anymore. I've never felt so alone and it makes me mad because I'm using the little energy I have left in my body and putting it all in this relationship I recognize I need help but I thought he would be more supported. I try not to text him so much or ask him to come over to see if he will finally just miss me and come home. I haven't slept or ate in 4 days. I'm down to 95lb I'm emotionally exhausted and just want things to get better. He has changed since that night and its like if I stop trying he will be gone. I just want support he has seen me cry almost everyday just begging him to come home I can't be alone its only making things worst and all he says is things will get better. But he doesn't understand the anxiety levels I go through trying to just get out of bed is the hardest and I hate that my 3 year old has to witness mommy crying and asking where is his Devin.. What do you think?