<human>: So, my girlfriend and I were having some problems recently, and we were both pretty upset about them. It was mainly communication stuff, and I was pretty sure we could work it out.

 But this was before something pretty shitty happened.

She was out at a nightclub, pretty drunk (not an excuse though), and a friend of ours lunged in on her and kissed her. Obviously she didnt expect this, but she kissed back (for 8-9 seconds, with tongue). She told me that this was because we were having so much troubles at the time and for a split second during the kiss, she thought "maybe I could be happier with somebody else". She then pushed him away and immediately went home and cried, because she realised she'd made a stupid mistake and definitely wanted to be with me, not "with somebody else"... We immediately blocked contact with this friend though. But I still feel really shitty that she kissed back, even if she was confused about our situation.

What should I do about this? Is it as big of a deal as I think it is? We really love eachother but it may take me some time to get my trust back with her...

Can you give me a shortened version of the text?
<bot>: Somebody kissed my girlfriend when we were having problems. She kissed back then pushed him away after 8-9 secs. Should I break up?