If she's made up her mind that she doesn't want to work on the marriage, as you say, then a gift for her on Valentine's Day won't mean Jack Crap to her! No romance. A simple card generic card with no romantic sentiments will be fine...if you must. "Hope you have a nice day" or something like that
"Always go straight forward, and if you meet the devil, cut him in two and go between the pieces." - William Sturgis, clipper ship captain, 1830's.