'Grey's Anatomy' season 13 episode 15 spoilers: Alex warns Meredith about Nathan

Meredith (Ellen Pompeo) will be caught between her best friend and soon-to-be-boyfriend when "Grey's Anatomy" season 13 returns. Meanwhile, it appears that the show has doomed — and will continue to doom —married couples since it first began airing.

When "Grey's Anatomy" season 13 returns this Thursday, Meredith will be caught between two significant men in her life, Alex (Justin Chambers) and Nathan (Martin Henderson).

As seen from the promo for episode 5, titled "Civil War," Alex teases Meredith of wanting to be with Nathan, which she playfully denies. But later on, Alex comes to his person and tells her that Nathan is a snake, leading Meredith to confront Nathan with rules to abide by if he wants to get anywhere with her.

For a long time, there have been speculations suggesting that Meredith and Alex will soon develop romantic feelings for each other. Could it be this moment, which is why Alex is suddenly getting in the way of Nathan to get to Mere?

According to Chambers in an interview with TVLine, "anything is possible."

But even though the actor sees Meredith and Alex as friends who can easily become lovers, "Personally, I don't see that [happening] right now. I think it would be kind of strange," Chambers added.

Even Pompeo agrees with her co-star. In a previous interview, the actress shared, "I think they're too close... too much like brother and sister."

But Pompeo noted that if executive producer Shonda Rhimes chooses to build a romantic relationship between her character and Alex, she is fully on board.

Meanwhile, it appears that "Grey's Anatomy" has broken down all married couples on the show.

As noted by Hidden Remote, the sustainability of marriage has always been an issue on the show, with the most recent married couple — Owen (Kevin McKidd) and Amelia (Caterina Scorsone) — at the brink of a divorce only after a short period of being married.

Looking back at all the married couples who have had their own arcs — Cristina (Sandra Oh) and Owen, Callie (Sara Ramirez) and Arizona (Jessica Capshaw), Meredith and Derek (Patrick Dempsey) — none of them are happily married now.

Will Owen and Amelia be the ones to break the cycle?

"Grey's Anatomy" season 13 returns with episode 15 on March 9 at 9 p.m. ET on ABC.