On the subject of the spouse being led astray by the evil OP, here's a story I read ages ago.
A writer was asked in an interview if she didn't feel angry at the woman who had stolen her husband, and she replied -
"Stolen? What? Is my husband a piece of candy, to be stolen????"
That always cracked me up, her forthright answer, and I know it is utterly true.
In my case though, OW no.1 was my friend, and I have to say that people do not do this to their friends (umm .....yes they do!!!) I once, and only once, rang her up and told her she was the friend from hell, and that she and H could rot there for all I cared. She started to tell me that she would not accept any responsibility for the breakdown of my marriage, but she sure as hell was NOT a friend to our marriage in any way, shape or form. And a friend does not pull/guide/tempt people out of their marriage with another and into a R with them instead.
Livnlearn
"The unexamined life is not worth living" - Socrates