I'm new here and need some advice.

Hi I really don't know where to start really. I'm scared in a way I know I'm in a toxic relationship it feels like it sometimes and I dont know what can I do. I've been with my partner 6 and half years now and we have boundaries in our relationship due to his actions in the past and cheating on me not just physically but every chance he would have he would do things and chat to others flirting specially while he was at work. We split up for 2 months then got back together I thought I'd forgave him as he changed hes ways he has been perfect our relationship been perfect when we are our little family except when we argue. We have boundaries to keep each other happy but he has this pattern of letting others come between us like I said every chance he gets he flirts or gets too friendly with others. We argue constantly because of the people he work with I'm not happy with how inappropriate behaviour /chat goes on with hes work team and he dont see anything bad and say they are adults I shouldn't get angry because it doesn't involve me. When we argue he gets very verbal abusive towards me and say it's my fault he gets that way he also have really bad anger issue when he gets angry. I try so hard to help him through it but seem impossible every time we argue I can't cope with this anymore i have my 9 yeald old and 2 month baby girl i also suffer with SVT and I feel horrible every time we argue I dont know what to do anymore. Should I just accept how hes work team is and how he seem to be ok with it even knowing how I feel about it? Should I just ignore it all?. I'm lost I cant keep arguing like this anymore.

I appreciate any advice. Thank you.