Sleeping around or with anyone is not such a big deal Olive. There is no question of morality or of using anyone. There has to be a willing party too to be 'exploited' as you think it was. And he says that she has been with him from the 'beginning' which is a couple of years or so.

Even if their living together for so long might not confirm to your ideals, he is likely someone who cares for her.