40 Days and 40 Nights (2002)

Matt Sullivan's (Josh Hartnett) last big relationship ended in disaster and ever since his heart's been aching and his commitment's been lacking. Then came Lent, that time of year when everybody gives something up. That's when Matt, a guy who's never been able to finish anything, decides to go where no man's gone before and make a vow: No sex. Whatsover. For 40 straight days. No touching. No kissing. No foreplay. No fooling around. No self-gratification. No nothing. At first he has everything under control. That is until the woman of his dreams (Shannyn Sossamon) walks into his life. Now, with everyone betting he won't finish what he started, he's just trying to hold on, and hoping she's willing to hold out.