When you're a big Hollywood star, it's probably hard to have a "normal" relationship. Everyone is nosy as hell, the pool of people you can relate to is small, and there are millions of eyes on you, waiting for the downfall of your relationship. So, when you meet someone who gets you, it makes sense that you want to make it official. And sometimes that doesn't work out. And again, and again, and again, until you've purchased enough engagement rings to make Thanos jealous.