I [24M] think my girlfriend [23F] went to a party and had sex with someone while drunk

Throwaway account. <br><br>So she came back from a party. Said she had sex with someone at the party but they used a condom. She said she was a little bit drunk. She was with her friend and said her friend was jealous over another girl flirting with her bf. So she went off and hooked up with some random guy. I asked her if she knew the guy and she said yeah she had met him a few times. This was the first time they hooked up. She said they had sex in a bathroom but sorry can't remember any other details. I'm trying to get her to take an STD test but she's being stubborn about it. She said they used a condom and there's no way she has an STD. <br><br>We've been together for almost 7 years. I'm wondering if this is a deal breaker? I'm upset about the whole situation and just don't know what to do.<br><br>Edit: I'm just upset about the whole situation because it feels like she cheated. She went to the party and hooked up with another guy. She said she was drunk but not too drunk. I'm just hurt over the situation.