Cole may still love Alison, but I think he also realizes that she's not good for him. I think he misses his past with her, but it wouldn't be smart to be with her now.
A wise man once said "sometimes it's right to do the wrong thing"
Maybe it's right for him to stay with Luisa. I think he loves her too and he admitted that he can't trust Alison and trust is important in a relationship. Yes we could argue the trust issue from Luisa's side, but this is more about Cole at the moment.