I don't understand the concept of being "Trapped" in a marriage.
Seriously, if its not a period movie...how can one be trapped in a loveless marriage. Dude, just get divorced. How are you trapped? Makes no sense to me...unless its like the middle ages where either there was no divorce or women had no rights to leave their husband...or you're the King & Queen and divorce just isn't done. Or its one of those political/arranged marriages where a peace treaty hangs in the balance. Outside of these reasons dictated by the history of the period...I can't see anyone being trapped.
I mean, if you're that miserable (and they clearly are in this movie), just leave. What's the problem?!