The guy probably has no idea he is offending you. Some people flirt just to let others know they are likeable and attractive in general. Most of the guys I know who make comments like you’re describing do the same thing to half the women in the parish, and to all of those over the age of 70.
If you let him know that he is mistaken about what kind of behavior you like, that will probably do it. If it does not, you can be a bit more direct. If it takes a 2x4, though, it takes a 2x4. Men have no right to make personal comments towards other men’s wives. “Nice” is not a carte blanche.
Direct honest communication is not hurtful. Just graciously let him know your thoughts. The chances are that he’s only trying to be kind, and does not realize he has crossed over into making you uncomfortable. Give him the benefit of the doubt until he proves otherwise.
“If I were single, I’m sure God would be steering me right toward the husband I have, Bob. Keep on looking; he’ll find someone for you, too.”
“Bob, I know you didn’t know this, but I don’t like pet names like “darling”, except from my husband, OK? I know people use them all the time, but I don’t like them. And unless I have tissue paper dragging from my heel or baby food on my forehead, I would rather that only my husband comment on my looks, OK? It is just something I do for my marriage, it is kind of unusual these days, but I feel quite strongly about it. It is not up for discussion.”
Then there is the more direct: “Well, as it turns out, I’m not single. Ninth commandment, Bob. Keep moving along, or I’ll ask Fr. Mike to tell you himself cut it out with me. I’m getting tired of this.” (The 2x4 is actually asking your pastor to tell the guy to cut it out. You should not have to go to another Mass to avoid this kind of thing.)
As for the e-mails, you can block him. That might be the best way to go.