One of my new SP providers who has been reviewed here before told me you would be surprised how many of these girls have serious boy friends or husbands!
I was shagging one in every hole (she has been reviewed here as well) for a long time but then realised she had been living with the boyfriend and then I stopped seeing her as I felt sorry for the bastard guy!
What would you do?
It wouldn't bother me in the slightest. Why should it?
You broke the first rule of punting: apart from being decent to the girl in a booking you are merely there to pleasure yourself (and if your pleasure extends to giving her some too, then that too). It is a paid transaction. Nothing more, nothing less.
Unless you think she is being forced or coerced in some way, when you've paid your money, fucked her and left the premises your liability/interest ends there.
Worrying about whether a girl has a bf or husband is neither here no there, that's up to her (and hopefully her old man knows what she does). It's a matter for them, NOT for you. It might pay for their posh holidays, it might pay their mortgage, it might give her old man the right horn.
If something as negligible as this is putting you off then I think you're also at great risk of that great punting catastrophe: Emotional Attachment Syndrome.