If my partner was video chatting with a friend in a sexual manner I'd consider it cheating.

If he's doing it with a Stanger and paying her I'd still consider it cheating.

It's not the same thing as porn. He interacted with another woman sexually. That fact that he paid her for it doesn't make it any better.

She deserves to know he stepped out of their marriage so she can make a informed decision on if she even wants to try and fix the issue at this point.