Nor would I Miner, nor would I.

He has obviously broken her trust.

He will be lucky if she gives him a second chance to do it again and she will imho be a fool is she gives it too him, who knows what other things he will do to breach her trust in the future.

By bringing other partners into the relationship and or covorting behind her back with others he has allready exposed her to the possibility of std's that she did not knowingly consent to if nothing else.

We may have our differences conserning some of the finer points of what does and does not constitute a minor or magior infraction and what punnishments if any revolve around such issues when it comes to certian things in D/s and M/s relationships, but in this regard I am with you 100%.