if he has a girlfriend, per one of your other answers, then adding his other friend would open him up to cross talk. So even if what the two of you talk about is benign for his current girlfriend relationship. She may be the jealous kind, and if the conversation from common friends get's back to his girlfriend then he has home life problems. That is the best scenero, the others get progressively less attractive for you.
uh idk maybe cause he has a seceat and told his feiends and then they would tewll you i guess
He's probably cheating.
Thats complicated then.
There's definitely something up
jealous i think