I have been with my girlfriend officially for 9 months but we spend about 3 months together before hand.
I fell madly in love with her and she fell madly in love with me. For the last month or 2 I have acted a bit different I got cranky over the smallest things in our relationship almost every day I can’t even think of an example that’s how stupid it is..
So last week I noticed she was a little more distant then usual and it got me thinking it was my behaviour so I sat her down and told her that I was sorry about how I was acting lately and that I have no explanation for my action and I will become the person I was before (the real me) she said to me that she would have to see it to believe it. I was more than happy to prove to her the real me! Then a few days later I find out she was txting another guy I asked her about it and she wouldn’t tell me anything so it turned into a big deal.. she finally told me that she met up with him on the weekend and that she kissed him, when I asked her why she said that she was un happy in our relationship and it was nice to have an outside opinion then things went from there.. I asked her why she didn’t come to me and tell me she wasn’t happy because things would have changed a lot earlier, she insist that she did speak to me about it.. she said that she was sorry blah blah blah, I do still love her and I don’t know how I will feel about what she did later on in life but I still want to go ahead with our relationship because it was so good before I was acting different and that’s what track I thought we were heading toward.. she said that maybe a little break is in order because the damage from how I was acting might be too much and she needs for the feelings to come back to her.. do you think that she wants a break for the better of our relationship or do you think that now I’m out of the road she can pursue this think with the guy she kissed?
To clear other things
The damage she is talking about was pretty much my mood
I never got physical or even really raised my voice
Her kissing the other guy is a big deal but that’s a whole other story
She has two children from her last relationship were she was hurt very bad and he still has a go at her every chance he can get. So she says she is scared of being hurt again and I guess she won’t take any bull.

What should I do?

Move on.

Breaks typically go nowhere except a breakup. My biggest concern though, is that you're still willing to be with her after she cheated on you.