My girlfriend has gone to a Halloween party and some fucking guy I absolutely hate is going to be there. Second time in 2 months she's been to a party with him. He's one of those 'touchy' type of people and loves to hug, lift up, etc my girlfriend, I fucking hate him. When I asked her what happened at the last party she said "oh, just danced and stuff" but other people who were there say "just dont worry about it". What the fuck does this mean?

I feel like fucking shit right now. Just sitting here alone and fucking frustrated as we only have sex once a month.

Does it seem like she is cheating? I feel like she is. Is it even worth being with this girl?