<human>: Can you give me the gist of the text in a nutshell?

Basically me and my ex of 2 years broke up a while ago (about a year and six months ago). I since moved on but every now and again something reminds of the break up, and how she was sleeping around with many of my class mates at the time that i was not aware of, and no one told me, this upset me as it showed who really where my friends, and I wasnt really surprised, but that's not the part I'm worried about, its just the hurt, it comes back and upsets me and even tho I know she won't say it, I know it upsets my GF or at the very least makes her uncomfortable, is there anything I can do? Will this go away? Or do I just have to live with it?
<bot>: exgf and I broke up badly, some of the things said/ done suddenly come to mind and upset me out of  nowhere, how make stop?