Turnabout is fair play.

Dana can finally see what he had done with Jane...

She was tied to a tree by her arms, with her body bent over at a sharp angle.
A gag was in her mouth.
A bar was tied between her legs to keep her spread wide open.

"What is this? What are you doing," Dana asks.
"I know why you two hate each other. She fucked your husband."
"Ex-husband now."
"Right. So the only way to work through your issues with her is to fuck her with your cock."
"I'm...I'm not Gay."
"Neither is she- obviously. That's not what this is about. Your ex-husband got to fuck her, so now you do too."

It makes an odd bit of sense to Dana, who's too conflicted to do much as he pushes her closer to Jane and starts to insert the 'cock' into her Co-worker's pussy.

"I've never...I mean..."
"You know how men fuck women, I'm sure. You know how you like it, right?"

Dana blushes, in part due to the fact that she's bound naked in front of this guy.
She's also very nervous- obviously.

She starts to try to mimic what she likes men to do to her in doggy position and Jane seems to enjoy it, in spite of the circumstances.

"I think you're both beginning to like this," the man says with a smile.