I feel a little bad for the guy. After all she was in HIS bed and it doesn't sound like he "forced" her to have the sex. It's hard to imagine she didn't know he was having sex with her or that she couldn't tell the difference between the two guys or that she didn't even open her eyes during the sex. Sounds like if her first "lover" hadn't returned she wouldn't have minded.

Was it established how much it would have cost to have had the sex with her permission? Dinner and some drinks at the night club couldn't have cost more than a $100 or two.

The punishment to me sounds a bit excessive.

Now if he FORCED sex on her, that's a different question (although I'm still not sure why the other guy had her in Corvo's bed). Whole thing sounds a little goofy.