Will i ever get over this....should i stay with him if not?

okay so I was dating this guy for about a year and we broke up for 3 months and were in the process of getting back together when he goes and hooks up with another girl...he than tells me he doesnt want me anymore and continues to not speak to me and pretty much ruins my reputation with some people. we havent talked for 4 months and he recently texted me and we have been hanging out. I know he was seeing this other girl and they did sleep together. i still love him and when we are together i am really happy. the only thing is i can't get her out of my head. she is everywhere and just yesterday we were hanging out and she texted him, i can't even explain the feeling that came across me, it felt like my heart dropped and it makes me so sad. I brought it up to him and he says there is nothing going on and he will do anything to be with me again. He tells me he loves me and he is sorry for screwing everything up....will i ever get her out of my head? everything he did to me the past four months hurt the worst something has ever...i hated him during that time and had to go through counseling and was depressed....but i do still love him and I don't know if i should get back with him....what are your thoughts??