I can only give you a slice of the experience I've had in my family with bipolar disorder. Most of my mother's sibblings are bipolar and most of them are alcoholics or drug addicts. Even though they are all medicated on lithium, which seems to control the manic phases rather well, only 2 have managed to stay clean. The rest are still drinking, while taking medication, and their spouses have elected to stay with them. Those are not happy marriages....
You say she has changed her behaviour since starting the meds. So, she is perhaps ready to work on herself and her recovery. There's nothing in there about repairing the damage to your relationship. That usually comes later, when recovery has been solid for a long while...are you willing to wait that long to see what happens?
If you're unsure, then do nothing. More will be revealed.