<human>: Me and my boyfriend get on great. We have been together for 5 years and he is the rock in my life. He helps me get by and deal with all of my problems and I also do the same for him. A while ago, me and my boyfriend went out for a few drinks. We both recognized people we knew there and got taking to others and basically had fun, as well as really drunk. 

At the bar, I was getting a few drinks for my boyfriend and some friends. As a thank you, one of the people I was getting a drink for gave me a friendly kiss on the cheek and wondered off to enjoy his night. I assume friendly, as he was talking to me and my boyfriend all night and it was just a quick drunken smooch on the cheek before wondering off. At the time, this was no big deal for me, I didn't even think twice about it. I was having fun with my boyfriend and it was a fun night.

With an awful hangover, I remembered this late on the next day, and felt a strong sense of pain and guilt for not telling him. Although I understand that it was nothing, guilt keeps crawling back in because I tell my boyfriend **everything**. Not because I have to, but out of habit. He really is my best friend and the only person I can really talk to and tell things to. I feel like if I randomly bring it up he'll over-react because I've left it so late, and now I've gotten myself in a horrible situation. The anxiety about the whole event is completely destroying me and is causing me to have regular negative thoughts. Every time he smiles and acts like his usual bubbly self, all I can think about is how bad of a person I am. If i think rationally, I can usually ease these feelings for a bit, but they only come back later. 

What should I do? Or, how can I bring this up without sounding completely insane?

Can you provide a brief overview of the text?
<bot>: Feel bad for not telling my boyfriend about a friendly peck on the cheek. Left it for too long. Need help and advise with how I should go about this.