Guys, Why my ex's friend is trying to sleep with me?

Pretty self explanatory question. My ex broke up with me but him& his closest friend still keep tabs on me which I don't care if they do, but when I've tried to talk to my ex's friend about missing my ex and how he has a few things still here, telling him I'm sorry I talk so much about my ex to him he just jokingly tells me "you need something in your mouth" and has made other comments about how he hasn't had a bj in a while but he has a girlfriend and I told him I'm not one to do that type of thing, not one to be a home wrecker. I thought guys had a "bro code" where they don't do this type of thing with their friends' ex or anything. I'm definitely not going to engage in that as if I did, it would ruin any chance I have getting back with my ex and ruin other friendships. I just don't understand why he's trying when he has a girlfriend himself. I'm not that type that goes around with my ex's friends/our mutual friends.

Guys, Why my ex's friend is trying to sleep with me?
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