<human>: Could you distill the essence of the text into 1-3 sentences?

Broke up with my GF of 2,5 years today after I found out she had a relationship she secretly started 2 months ago.

We've had turbulent years in which she did try to break up a few times (love blinds, but okay)
She was my first real relationship and I was her second so naturally things didn't go as smooth (and I was going through a lot of bullshit at the time) and we had a lot of fights but always managed to solve them.

now it just won't be solved, I wanted to try again but she didn't so we split disastrously.
<bot>: (now EX)GF cheated on me with another guy even though she promised we would work out the problems in our relationship and as of now I just want to ask: How do you deal with this?