It does not have to be full * if you don't fancy that , as there are many other ways to give pleasure, it may be that you just want a cuddle and to feel the warmth of someone, there is no time limit just enjoy yourself. I am perfectly happy if someone else is present in the house, as I am very discrete and respectful so if you husband is disabled but happy for me to help you that is fine, equally we can meet on our own if you prefer.
Perhaps the first meeting is just tea/coffee and a chat to see how we get on, that way we can see what chemistry there is between us