Why would anyone marry an AI?

I don't get why AI marriage is even a concept. My understanding of marriage is that two people apparently love each other and want to make a covenant to spend the rest of their lives with each other. Even if I'm wrong, I can see how marriage works out for two human beings who have free will, who take part in a relationship by choice, who choose to love each other. <br><br>But what would a relationship look like between two humans with a machine?