Although same sex marriages are now legal it seems that, under UK law at least, adultery hasn't kept up with the times. UK law defines adultery as sex with a person of the opposite sex who is not the person you are married to so sex with someone of the same sex cannot be adultery and is NOT grounds for divorce though I suppose you might argue that it's unreasonable behaviour which is grounds for divorce. Bizarrely, this definition still applies if you are in a same sex marriage.

I suppose that if you've said traditional wedding vows adultery is a contractual violation.

I'm reminded of the silly question, "If adultery's illegal, what does that make infancy?"

Seems very odd that you can marry someone of the same sex but you can't commit adultery with someone of the same sex because, somehow, it doesn't count. I believe it varies from state to state on America.

That is odd, Bob. I haven't heard much about "adultery" any more, have you Geoff? I wonder if it is even used as grounds for divorce these days. I mean, you can get a divorce for many reasons.