Everyone's experience is going to be different in this area, I think. Some people have someone at their highest weight who supports them on their journey--that's what I'm hoping, but I don't really know. But whatever he thinks or does, I need to do this for ME. If he likes the result, great. If not, someone else will, I believe.
I don't think you should wait to be on a dating site or meet someone--go for it. You don't know for sure even that the guy went away because you told him about the weight-loss surgery--it could be that, it could be that he just met someone else, it could be that his wife discovered what he was up to, it could be that he broke his arm . . . it could be that he realized you were more honest than he was. Doesn't matter . . .keep on moving forward!! And good luck!