Is he uncomfortable with you doing it by yourself or just at all? I mean, what does he do when you invite him to watch or join in? For me, (R3, M1) I almost never MB. In the beginning of the R, I did it in front of him (while he was driving, if you can imagine that!) only once or twice. Since then, I have felt way too self-concious to even think about doing it in front of him. It's funny to me how I could do it in the front seat of a moving vehicle only three months into our R, but now, 3 yrs later, I can't even think about it.