He wasn't marrying her. Even if she'd have him, which she certainly wouldn't, he had no intention of leg-shackling himself to such a difficult woman. She's always be racing off to save some new stray lamb, and if she even caught wind of the Scorpion's criminal associations she'd probaby try to save them, as well. She was a dangerous woman, never content with the status quo, and she would drag who ever was fool enough to marry her along for the ride.