<human>: I asked my girlfriend out like 3.5 months ago and a couple days later I danced with a couple girls. For whatever reason, it was really bugging me this past weekend that I never told her about this.

After the incident happened we had talked about how we felt about each other dancing with the opposite sex and agreed that neither of us would like it but can't control each other's decisions and that we trust each other to make the right choice.

After asking a couple of friends advice they recommended I say nothing about it, but it was eating away at me and I told her. I know it sounds like nothing really but it was just bugging me. 

After I told her she got pretty upset. I said that it was totally my fault and am responsible and it won't happen again. I'm not that type of guy to do these type of things and I just hated seeing her hurt. She told me that she had even called her mom because it was bugging her. Eventually she said it was fine, she appreciates me telling her, and asked me 'how does she know it won't happen again.' 

Right now, we are both on the same page and care a lot about each other. I guess what I'm asking is what can I do to make it up to her? I was thinking of taking her out to dinner. Should I write her a card saying I'm sorry? I just want to show her I care about her deeply even though I haven't been the best bf as of late.

Can you give me a shortened version of the text?
<bot>: Told my gf I danced with another girl 3.5 months ago, she got upset but we are ok now. How do I make it up to her?