Loki has a horrible, massive and crippling low-self-esteem. He doesn't let it show, but he literally believes he is so horrible and ugly etc that no one would love him.
Then, Loki meets a man who is a horrid rude slob. Fat, I think, middle-aged, beer-guzzling Midgardian. And this man tells Loki that Loki is beautiful. Loki, due to his low self-esteem, believes that this man (who is the only one who told him he was beautiful) is the best Loki could ever have. So he enters into a relationship. Not out of love, but literally out of 'this is the best I can hope for'.
Does this ring any bells for anyone? I would really appreciate some help.