Fans of Grey's Anatomy were left with a major cliffhanger that tugged at their heartstrings during Grey's Anatomy Episode 15. One question was on their minds: Did Derek cheat on Meredith?

During Grey's Anatomy Season 11 Episode 16, which was aptly entitled "Don't Dream it's Over", fans would find out whether or not Derek did cheat on Meredith. The couple have had their share of ups and downs before finally tying the knot. Even then, Meredith and Derek had trying times which constantly threaten to tear their marriage apart. Could Derek's suspected infidelity end things once and for all?

While Derek did come home for the first time after being assigned to D.C. because "he left his keys." fans of the series couldn't help but speculate that this was in fact, "not so innocent". Fans of Grey's Anatomy know that Derek is no stranger to adultery. After all, Derek did cheat on his first wife, Addison with Meredith in the first place. How will Derek explain the happy sounding woman answering his phone?

Meredith Grey then confides to friends about her dillema, and while they are supportive towards Meredith, they do stress one bittersweet truth: Derek has cheated before. Meredith and Derek may have an epic love story, but this does not shake Meredith's worries. Fans cannot blame Mer for being paranoid. After all, there is the old adage: once a cheater, always a cheater. Has Derek found another woman on a side? Will Derek and Meredith have a fallout next week?

April and Jackson are trying to come into terms with their son's death. After having some hot car sex with her husband, one cannot help but think that April has changed. How long before she crashes and burns?

Do you think Derek cheated on Meredith? What did you think of Grey's Anatomy Season 11 Episode 16? Let us know in the comments below.