toxic relationship and a lot of underlying issues out. out of ideas out of hope

I’ve been battling depression for aproximately 7 years but it has gotten progresively worse in the last 4 years I’ve been with my fiance. I’m very insecure and my fiance is a very attractive man who made the mistake of cheating on me once in the past and I’ve attempted to forgive him but I don’t think it’s possible for me to actually forgive him. its been 3 years since he cheated on me but girls flirt with him and try to hookup with him constantly and its starting to take a huge toll on me I love my fiance more then anything but I think he’s kind of a flirt and gives women the wrong idea even though we are from a small town and everyone knows we are together. everytime I see or hear about another woman flirting with him I get really angry and upset I start to cry and shake uncontrolibly I need some advice on either how to split from my toxic relationship and not feel so upset or I need advice on how to deal with my anger cause its getting so out of control that sometimes I just don’t want to live cause I’m so inscure and angry and terrified of being alone. I know when you read this your going to realize I have a lot of underlying issues and emotions that i haven’t learned how to deal with and honestly I don’t know where to start I’ve had 3 councelors but none of them have helped I running out of ideas and hope