In the film, Tatum's character has to fight to win back his wife, played by McAdams, after she loses her memory of him.
McAdams, who portrays Cricket Carpenter onscreen, insists the couple's story is proof that love will always prevail.
She says, "Cricket woke up out of a coma and she had completely forgotten her husband. She had sort of just lost about a year and a half of her memory... so he had to win her back.
"They're still together, they have two beautiful children. They got remarried."
The Huffington Post UK has been given up an exclusive clip, which you can see this above.
And if you're in the mood for a pre-Valentine swoon, here are some inescapably romantic pics from the film below: