"It's not exactly common in the US - certainly not where I live. I too, am the hinge of a vee.
For the first couple of months of dating my boyfriend, I spent 3 days a week at his place and then 4 days with my husband at my house. We have transitioned now to my boyfriend moving in with us. Only recently did we become out to all of our extended family - but I definitely thought it important that they knew, so we wouldn't have this dread and anxiousness hanging over us. It would just temper our happiness too much. If your boyfriend has said that he would have a difficult time choosing you over his mother - well, you know where you stand. I guess you need to decide whether you want to have that worry or not."
It would certainly be easier if I could seperate the week between them. Staying one week a month in his country is the best I can do so far, exept for holidays. I think it can work, at least this year. If we moved together all of us I would feel a need to tell family, too. Well, as a matter of fact I feel a need now as well, but I want to take it slow so that I have gotten used to it myself.
What he actually said was more along the lines of that he feared that if he was open about living with (and hence choosing) me, he could not go back home. I am grateful that he shared his concern with me, but of course I worry, too.