I found out the guy I was dating was engaged & due to marry in a few WEEKS – I made him pay in the best way

FINDING out that the guy you're seeing is already taken is a huge bummer – and even worse is learning you're the "other woman."

But one New York singleton tells The Sun that she refused to take a man's two-timing lying down – and managed to make him pay in a pretty creative way.

Jenna, 35, was on a girls' trip with her friends in Nashville, Tennessee this year when they befriended a bachelor party group at a bar.

Jenna started talking to one of the men and they immediately began flirting.

"I asked him if he was single, and he was like, 'It’s complicated,'" Jenna recalled.

Not one to bother with a cheater, Jenna made him clarify and the guy insisted he was actually single – and all of his friends backed him up.

";I took this as, he and his girlfriend were on a break, or he just broke up with someone," she said.

After making out at the bar, the pair exchanged phone numbers and made vague plans to hang out later.

They did end up meeting up, sleeping together in the apartment where the man was staying.

Looking back, Jenna is struck by the fact that his friends were all there and knew what he was doing.

"All the guys were there. They all knew he was engaged," she said.

But she was still in the dark and went back home to New York thinking she'd never see him after that weekend – even though he lived nearby and said he was interested in meeting up again.

To her surprise, he texted her Monday morning. Now back to real life, she decided to do a little digging before their date.

"I Googled him and the first thing that came up was his wedding website," she said.

It listed a wedding date less than two months away.

Incredulous that he would cheat so brazenly, Jenna gave him the benefit of the doubt, assuming they must have just called off their engagement and not taken down the wedding website yet.

Yet when she confronted him, he admitted the truth.

"He was like, 'Oh s***, yeah, I thought you were in the same boat as me,'" she said.

Jenna gave him a piece of her mind: "I was like, 'I don't understand why you would think that. I was very clearly single, you definitely knew that.'"

She was devastated.

"Not even just for him, but more just that someone could do that," she said. "I obviously feel horrible for his fiancée, that’s obviously way worse.

"Being the other woman felt so cheap and dirty. I was used. It was very, very hurtful. That someone would disregard my feelings."

But even in the moment, she had the presence of mind to reply with a zinger.

"I said, 'My therapist is gonna send you my invoice for my therapy for the month,'" she said.

Then she sent him a Venmo request for $650.

While the Venmo request was mostly to make a point, Jenna was surprised when the guy fulfilled it, sending her the money.

She was so surprised that she sent it back.

Looking back, she said that she doesn't regret sending him the money back – but she does wish she's Venmo'd him for a higher sum in the first place.

"I wish I'd Venmo'd him more and kept the money. I regret not requesting $3,000 and keeping it. I'd have kept a more meaningful chunk of change," she said.

In the end, she dodged a bullet – which is more than can be said for the woman he was engaged to.