I’ll bite. Sure it’s “icky” - but if she’s over 21 - I figure that’s her problem, not society’s. Sure she could end up being pregnant etc. etc. - but this is NOT the same as abuse of a minor IMHO.
These people tie up a tremendous amount of court resources thrashing out their problems ~ the rich ones do anyway. The poor ones just have another baby somewhere else, or lock the girl in the basement.
If she was an adult, if he committed incest, didn’t she as well?
The big problem here is usually these relationships (?) if it can be called that start with years of conditioning and rarely wait until the child is 18 to begin.I’d lay money on it will come out later that Daddy started doing this many years ago and they were just caught.