Do I give my ex boyfriend and I another go or are these signs I shouldn't? Don't know if trust is there anymore....please help?

So I broke up with him around a month ago and we have still been talking a little bit and I saw him one evening where we had a huge chat about everything.

He has this weird obsession with other females (people he knows and celebrities) and it's like he thinks he's a bit of a player. He likes other girls photos which I have told him bothered me, went out and had a photo put up with him and his arm round another girl, and after I caught him talking to another girl on Twitter he told me he met her on a night out and that his 'friends' gave out his number. I do not trust his friends and they're all single. They're also all druggies and I know they persuade him.

I have told him this but since we broke up I saw he was still liking this other girls photo. He said he didn't know whose it was and if he did it then he was sorry. I feel like he's trying to win me back and saying all this nice stuff but clearly not showing it. He is also on holiday with his family and best mate at the moment.

The face that he was messaging another girl he met on a night out has kind of made me think I can't ever trust him again but he said he knows he was stupid and things will be different. What do I do?