@SheriGR, thank you so much for your help! To answer your questions --I got stuck on the tutorial the first time (which I discovered is common). So I restarted and went through successfully the second time. I successfully finished the tutorial, and continued on playing the same Sim, and added another Sim to the household as it suggested. I did not marry or try to move until I was in the actual game. But you are right that I'm not in the habit of saving the game. I should have saved it before I made any major changes. Total noob mistake! Now I will remember.
I wasn't aware of the Manage Households area yet - I will check there, thanks! But I ended up moving on and playing a new game, where I did marry and move house successfully several times. I think I may have hit a bug when I tried to move in with someone who had no home, is all. But part of the fun is discovering how the game works, right??
Thanks so much for the guides - I was watching some beginner videos and it's very helpful, now I'll check out Carl's Guides.
Jenn