Am I paranoid fiancé or should I have a reason to be

I’ve been with my fiancé for 9 years and have two kids with him. He’s a flirt and is outgoing . He’s mostly friends with females and I’ve caught him cheating on me once with one of the female friends he talks to. He says I need to trust him but sometimes I see these girls and I compare myself to them and blame myself for his actions and say am I enough ? . Should I feel this way or should I just ignore it .