Then you don't turn him into a vampire. It sounds like you need to reload your game going off what your saying. There probably is a work around, but your saying you didn't want to be a vampire in the first place. Reload your game. What are you playing on auto saves alone?
No I am not playing only with autosaves of course, and I didn't want to be a vampire, it just happened unintentionally but I just thought, ok, whatever I will just play vampire stuff since I can get cured whenever I want. So I continued that way. Played a lot of hours, did a lot of things after that. So it's a save from way back that I can't even tell which one now. Even if I find that save before I choose the vampires' side, my loss will be enormous in game. So that's not an option.
Actually I went back to vampire quests just for the sake of stopping dawnguards from attacking me all the time. I accomplished that, so may be I should just forget about the rest of the vampire quests. But I'm curious lol
If only there was a way to cure him back after completing the quest.
Just cheat on him with someone else that isn't a vampire, this probably is the best solution
Edit: nevermind I don't know if you can remarry, it looks like you can't. I don't know what to tell you, if your on PC there is the console, and mods. You definitely could fix your problem using the console I believe.