Can someone help me? I'm confused?

Me and my previous boyfriend broke up before christmas. and now he is saying that it was a HUGE mistake to do that. He wasn't thinking like this until the girl he left me for broke up with him for his best friend. But there is this other guy(devin)who likes me and i like him. But I think my feelings for my ex aree coming back and i think i still love him. Devin doesn't know i like him....but my ex now knows that i still like him. who should i date..my ex or devin?