I'm sure this will gross out some and set up others as judges but things like this take place. I grew up watching my mum sharing her husband, my dad, sexually (and in other ways) with her mum, my granny. It was a tradition among women in my maternal family not to be possessive in those ways and none of us complained if the female was left alone due to being widowed or divorced. I share my hubby with mum and my teen daughter has already agreed, when she marries, to share equally if need be. In any case, it will be my choice. Curiously, the men never complain :).