Am I crazy to think this?

So, the guy that I had been seeing for about almost a year and half ended things about a month ago. He told me that he couldn't love me the same anymore and that he had developed feelings for someone else. And me being the person I am, I ended things because I knew I deserved better than that. Well, since it's been a month. Things have not been easy for either of us. Going from a relationship where we were essentially like an old married couple that did everything together and was able to get into a groove to not talking to each other every day has been difficult. I know now that him stating that he couldnt love me anymore was untrue. I know he loves me and cares. And I still care for him. But I recently got into an open relationship with a guy from my past that I always had a thing for, but I don't feel like he's a guy I'm going to be with for the rest of my life. and I'm starting to look for a guy that I know i'll be happy with for the rest of my life, and I just don't think that he's the package deal. And I keep coming back to the idea that I was happy with the last guy and I've come to peace with what happened (I know for a fact that these feelings for the other girl are going away and he's moving on from them). I guess what I'm asking, is this crazy for me to think these things? I know that it takes time to fall in love and you'll fall in love more than once, but there's no one else I could ever be crazy about as this last guy. I don't know if my now ex is the one, but I know I'd be crazy happy to be with him for the rest of my life.