People who walked in on their SO cheating, what did you do? How did you walk in on them?

It was a late night, gaming with friends and their friends, everyone is enjoying themselves. My girlfriend, who I'll call Kayla, is in the room upstairs apparently doing her nails and getting changed. We're playing Halo Reach, and it's DMR and Magnum BTB. We had about 16 people there, and my best friend Jacob brought his cousin Ben, so he could get us with an extra Xbox and game and all. We were all playing on Forge maps I'd built.

Eventually we all started dying of laughter from our idiot group of friends abusing the Drop Shield and Armor Lock. Ben had to excuse himself, he felt like he was going to get sick from the laughter. He goes upstairs to use the bathroom. I almost got up because I remembered Kayka was upstairs and was spending a lot of time there, but Jacob said "Bro, why are you getting up? We're on no break! Ben is a loser, having to get up to use the bathroom. If you're truly dedicated, let's continue this!" and I have to say, I will NEVER back down from something like that if someone says it. I sit back down, and we continue playing, and eventually we even got ourselves some pizza, so we then we're living it up playing Halo and munching on some delicious food.

Anyway, then I realize it's been ages since Ben and Kayla ended up going upstairs. At this rate the match just ends, and I tell Jacob "Alright, I'm going to be real quick, don't worry mate." I say as I get up and walk upstairs to check on if Ben is ok, and especially see if Kayla is doing fine. I go to the bathroom, and it's opened, light is on, nobody in there. I can hear talking in the room Kayla is in, and I open the door, and see her making out with freaking Ben... I immediately scream "What the Hell is this!?" in complete anger. Suddenly, downstairs goes silent. My girlfriend looks at me, scared as Hell. I scream again, saying "Kayla, Ben... WHY!?", and Kayla says "Well... This is what happens when OP decides to not use the serious tag."

/r/AskReddit Thread