<human>: Background info- my boyfriend is the sweetest, nerdiest, cute guy in the world. Recently, his cousin and my sister had a fling, to which he didn't share any details with me. 

This morning, I saw he had a message from his cousin, and of course it peaked my curiosity to look... Thinking it was about sister. I know this is wrong that I looked. 

However, his message to his cousin last night was talking about another girl who his cousin recently became FB friends with. My bf, was asking his cousin if he had "fuc***" her yet? Then, he proceeded to say that this girl was sooooo hot. And if he could, he would fu** her all night. 

Seeing this made me sick. I didn't think my boyfriend thought that way, and it really hurt me. Trust me... He's never like that. Am I overreacting?

Summarize the given text in a few sentences.
<bot>: my bf m(26) told his cousin m(28) that he would love to f*** another girl.