The idea seems romantic, but the reality of it would probably be really painful. Real life is never as good as one's imagination.
Yeah. Chance 1 survives after, esp with lower falls. I can't imagine all the troubles and hassles after that stunt. Also, there's a greater chance one of them gets cold feet and they can't jump together.
There's certainly better ways to die with someone you love. Personally, if I had a lover we'd use exit bags, holding hands, even applying rubber bands so it'd stay together after we die. Tho if I had a grenade we might be using that too.