Why can't I say no!?

So my ex has been wanting to hang out and such since our breakup a month ago and I have been trying to stay strong and not give in but last night I did and of course we had fun just like we always used to. While we were driving to one of the places we were going to..he was like "I'll always love you" "I just want you to be happy in life and I tell myself that everyday" "I know we were happy together but I had to let you go". (We broke up because he needed to see if there is anything different out there, but he doesn't want a relationship with anyone, he needs to get his career in order, and those are just some of his excuses)