<human>: Well, we have a ~16 months long relationship, I've never done anything that I could be ashamed, never even called ex's and shit, and just some 30 mins ago I've found that she have fucked the shit out off some guy some 10 months ago.
I've cheated before, she had also, but I've guessed that this time it would be different.
I'm 27 and she's 31, we're living together paying bills and shit...the more serious relationship(t) that I've ever had.
How should I behave? 
Should I fucking brake something? 
We have just fought, and I feel bad because she din't cry about what she did...
What would you do?

Can you give me the gist of the text in a nutshell?
<bot>: My 31 GF cheated on me 10 months ago, me 27, just found out and confronted her and she didn't care about it