“Grey’s Anatomy” creator Shonda Rhimes warned us not to get too comfortable with Meredith (Ellen Pompeo) and Derek’s (Patrick Dempsey) storyline. But did we listen? No, and now we’re left here maybe even more broken hearted than Dr. Grey herself.

Episode 15 of the hit ABC medical drama concluded on a very tense note. After weighing the options of whether or not she wanted to have Derek in her life, the successful surgeon came to the conclusion that she’d rather share her victories with her husband than by herself. That’s when Meredith decided to give Derek a jingle. But to Mer's surprise it wasn’t her doting spouse that answered the phone but a mysterious woman.

“Who is this?” Meredith demanded over and over again before getting hung up on. This left viewers questioning if Derek had really cheated on his wife while working across the country. But how concerned should we be really? After all, it was previously speculated not too long ago that Meredith was the unfaithful one after she got caught not visiting Derek in D.C.

“I’m not cheating on my husband,” Meredith told Maggie (Kelly McCreary) who had accused her half-sister of being disloyal. Mer then explained that for whatever reason she just couldn’t bring herself to get on the plane to D.C. “I didn’t know how to tell anyone that I didn’t get on the plane to visit my husband.” So, instead of returning home, Derek’s wife booked a room at a hotel near the airport – where she spent the weekend alone and happy.

That caused us to wonder if Derek had an equally innocent excuse for the seemingly wretched situation. And according to a sneak peek clip of episode 16, we’re not the only ones inquiring his integrity! “I called Derek. A woman answered his phone,” Meredith tells Alex (Justin Chambers) and Maggie, who just so happened to be in the room during the time of the confessional.

“What kind of woman?” Maggie wonders to which Meredith responds, “She was perky. And she sounded happy and tall with a lot of great hair.” When asked what Derek had to say about the stomach churning phone call Mer revealed she hadn't spoken to him. “I keep going to voicemail. My short, twisty, mad voice keeps going to voicemail.”

The video concludes with Meredith asking her “person” if Derek could possibly be cheating on her. Meredith will struggle with this alleged infidelity in episode 16 titled “Don’t Dream It’s Over,” questioning if Derek could possibly betray her like he did his first wife Addison (Kate Walsh).

Do you think Derek has an explanation for the woman answering his phone or is he cheating on Meredith? Sound off in the comments section below with your prediction before tonight’s episode, which will air at 8 p.m. EDT on ABC.