Saw it on TV somewhere in the 80's in England. Not sure how accurate any of the details are
There was a love triangle: two boys and a girl grow up together, both boys fall in love with the girl. She chooses one of them and they marry. The other joins the IRA and ends up in prison. He gets one night off and is supposed to spend it at the home of his childhood friends. However he cannot bear to be near his loved one so he prefers to go back to jail.