Responses
If she gives back the heart, her lifespan will return back to normal. She would only live for maybe 100 years and Aiden would be left by himself for the next 1000 or so. I doubt that the story will go in that direction. It's always possible though...
Having said that, I do not agree with the choice that he made on his own. He definitely should have discussed with her first. He completely change her life without even a word. He's a real asshat
I kinda want to see MC find a way to give him back his heart. Although because this would be breaking a promise / oath, she would probably lose all of her magic, but I think that's a better outcome than forgiving him and living happy ever after. Too many stories like that, and too cliche. Women should not be so forgiving when the ML pulls shit like that (although this is never gunna happen cuz book and HE)