What do you do if your fiance has custody of two kids from a previous relationship whose mother is not involved and the kids won't let the pair of you have any time alone?

This has nothing to do with the kids, but the parent who has little to no control over them. If the children are young there is such a thing as bedtime and when a parent tells them to go to bed, then the kids should get hopping. Once in bed, then the parent can read them a story, kiss them goodnight and that should be the end of it. This should leave you both time for each other. As far as dating on weekends there is no reason the parent can't get a babysitter, and both of you can take in dinner and a movie or go out with friends. It's time to talk to your fiance and let them know you aren't happy with the situation and express you care about the children, but there are no boundaries set for them and you just can't take it anymore. Leave it in your fiance's hands because if you don't and get married, it's only going to get worse. Kids aren't stupid and they will play their parent like a fine tuned fiddle and the fights between you both will get out of hand over this. Have that talk! Good luck Marcy