Sometimes people don't get along with their significant other's parents.

It's not an entirely uncommon issue, and the reasons for a disconnect are often fairly simple: they have big expectations that you don't meet in some way, you don't share common interests or they're pushy about how you and their child should be living your lives.

One guy who wrote into The Guardian, however, ran into a fairly uncommon reason to butt heads with his girlfriend's dad: they used to sleep together.

The anonymous man, looking for "sexual healing" advice, wrote into The Guardian's Pamela Stephenson Connolly, "a US-based psychotherapist who specializes in treating sexual disorders."

He wrote:

"Five years ago, I went through a bi phase and used to sleep around with pretty much everyone that came along, including other men. This changed when I fell in love with my new partner, who is everything to me."

"I recently met her parents and halfway through lunch realized that I had slept with her father. I was going to propose, but when my partner and her mother were away, he told me to end it with his daughter."

"I'm obviously in love – shall I just ignore him, or tell my partner?"

"I am not sure you could ever have a comfortable future with your new partner."

"To tell the truth would be to court disaster: a probable break-up, plus the risk of a permanent rift between father and daughter and father and wife. Hiding the truth would lead to toxic secret-keeping that could be equally destructive in the long run."

"If this whole family was as open-minded and sexually open as you, it might be possible for you to become part of it. However, the father – your former lover – has made it clear that you will not be welcome."

"Walk away now, and avoid the massive pain that would otherwise be inflicted on your partner, her family and yourself."

Twitter couldn't believe what they were reading.

One can only imagine what the wedding would be like with the father walking his daughter down the aisle to their mutual lover.

Many people wished there were even more details!

Others had trouble believing the story was actually true.

Though Dr. Connolly told the advice-seeker to break up with his girlfriend, people on Twitter felt he should push through the awkwardness if he really wanted!

At the end of the day, having sex with your girlfriend's father could be a...good thing?

Good luck, advice-seeker!

We hope everything turns out okay.