As long as you're open and honest with your partner about who you are talking with :). If he was in the party with both the gf and friend maybe he was uncomfortable by some action. Telling someone who to be friends with is bad. Admitting its an action that makes you uncomfortable ok. Continuing to be friends with say someone who hit on you with your partner in the group would also be bad. Boundaries on emotional cheating are between the party and I truly hope the guy isn't crazy controlling her but maybe it's not black and white. Also she has him on snapchat as well so more than being an xbox friend. sorry to lightly play the devils advocate. just food for thought.
They don’t know if they’ll get cheated on and dumped