Need advice!

I’ve been in a relationship with my fiancé for close to 7 years we have one child together. We’ve always had a great relationship I’ve always been able to tell him any and everything he’s been my rock. Everything went down hill 2 years ago when I found out he cheated on me and had a baby on the way. He’s never cheated before so I was completely taken off guard. The whole situation took me by surprise and literally broke my heart! He’s been trying to make it up to me & saying it was a huge mistake and how he doesn’t want to lose me. I’m so torn because I want more than anything for us to get married and continue raising our daughter together under one roof. In the beginning I tried to push through the hurt and I agreed to say if he promised to never do anything like that again I figured that with time I would start to feel better about the situation but I’m actually feeling a lot worst now. I’m staring to second guess myself if I made the right decision by staying. Him cheating on me has also made him feel insecure & that I’ll cheat back which is something I’ve never done so it’s a bit annoying to deal with his insecurities now because it’s all coming from him cheating on me and feeling guilty about it. I just want my family to work out I and want things to go back to how they use to be when I was actually happy. I literally have nobody to talk to this issue about because of how embarrassing it is for me. I need some advice on what I should do 😩