Do I stay or go?! Can sleezy boyfriends really change?

[bee]

I'm 18 his 19.been together 8 months. The first couple months were rocky, social media got the best of us and both enticed people to get attention of another person. This became very obvious around the 2 month to eachother so I asked him about it yet he said he was texting girl 'friends' I knew deep down this wasn't true yet swept it under the carpet. I had to trust him, he was starting Uni, went on a lads holiday to amersterdam and went to Leeds. Howevsover time it got the best of me when things became more apparent to i retaliated and innocently spoke 2 boys. both learnt from out mistakes and 6 months in things got PERFECT,we were/are totally in love! Then on the day after our 8 month anniversary I found these texts, him begging to meet up with girls& telling him he missed them. I confronted him, he told me he HAD met up with a girl & planned to do so with others but never did actually did
Itime has passed and were both changed people, I've tempo dumped. WHAT DO I now? Feel a fool