Too much..

My husband was caught sending pictures and emails to online women last July/October while I was pregnant. We separated for 8 months while he was deployed, when he came back we reconciled and I told him then if the tiniest thing happened as far as lying I was done. Well, two weeks ago he looked up his ex girlfriend on fb(no messages) he said he was just curious. Mind you he had a 3 year relationship with this girl and they lost their virginity to one another. I'm not happy, at all. I lost my virginity to him and we started a family... I want to leave back to my hometown but he's begging me to stay... I would love opinions on this because I am at war with myself on trying to make it work or get out and be truly happy..