Title of a movie : trap in a dugeon (love story i think)?

Help,,.. forgot the title of this movie, where

i think its a love story? or action.? all i remember was the 2
characters..
uhh,,. its somthin like a movie in year 2000 up...

there was a men and a lady, (i don't think they're couple) who were
trap under (somthin like under in a desert structure?) coz, i saw much
of desert sand. they were underground

they were trap there, and they want to go out,. and they had an
intense Seks there it lasted so long.. haha :D

the lady survived though..., through a small opening ( i dont think
how they find it or they might used their strength to make that
opening)

the man , remained inside the (cavern,old structure underneath the
desert.. whatver) because he can't escape, go out because of the sand
pushing him inside (desert sand i think)...

the man was buried alive inside and the lady had survived ..

the title? .. uhmm please help? just get my thought?? :(