I think you've got some other things to sort out first.

If the woman is seeking revenge on the man, she obviously knows him. Why would the man put himself in the hands of someone he's wronged?

I'm uncertain as to who is trying to seduce who. The man seems to be a willing participant.

If the motivation of the woman is ruin his marriage, why would she give the option of $ to not reveal the tape? Why not just go straight to the wife? This would leave out the option of going to the police for either party.

It also seems a little odd that she's the one having sex with a man she detests so much. Can't she get a prostitute to do the dirty work for her somehow? Or maybe get him to proposition her on tape somehow? Actually having sex with him just seems way out there.

Whose POV is the story going to be written in? Who are you considering to be the protagonist and antagonist in this scenario?