Please don't be nasty. We've been together 5 years. 3.5 years ago I found out (not from him) that he'd cheated on a night out the weekend prior. I confronted him and asked him to tell me everything that happened. He told me they kissed and that was it. I sat on it for a day and it didn't feel right so I asked him again to tell me the whole truth, he then said she'd given him oral and they slept in the same bed. This might seem daft but because they hadnt actually had sex, he'd finally been honest and really did seem sorry, I forgave him. We went on to have a pretty great relationship, moved in together, got engaged and had 2 kids. We never really talked about it again, he said he didn't like talking about it because he regretted it so much which I thought was fair and I didn't really want to talk about it again either. I purposefully didn't tell most of my friends so we could move on and start fresh from it which is why I'm posting here and not talking to them.
This is going to sound weird but last night, I couldn't sleep because I had a weird, sudden feeling that he'd lied to me and they actually did have sex that night. I barely even think about it so this was really odd to have popped into my head. So anyway today, I sat on it and tried to forget about it but I couldn't. I asked him straight up and he eventually said yes, they had. I left the house for a bit and we haven't really spoken since. Am I being absolutely ridiculous and childish about this? I already knew he cheated one way or another and I got over it, is this really that different? To me this feels so much worse and I hate that he lied to me. It feels like I've been cheated on all over again. I feel like our entire relationship since then is a bit.. tainted? I feel really embarrassed and don't know if I'm being over dramatic, I just need someone to speak to