Why would he cheat in my house?

My then boyfriend (now ex boyfriend) and I were together for 2 years. His company shut down and I was trying to help by working more. I didn't move in, he did. It's my house.

The extend of the cheating was disgusting. I didn't catch them but found some other girl's dress and other evidence. His lie about trying to surprise me with a dress would've worked if it weren't for one detail he got wrong about me again: I HATE DRESSES and was tomboyish as a kid.

He invited her my homemade meals on 3 different occasions. The last one was my apple pie, seafood Chowder soup and leftover fried rice. They used the bathroom, my bedroom and who knows what else happened. Why would he do that in my house?
Why would he cheat in my house?
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