Loki, despite what he says, was quite the... curious child. This is why he tried to take over Midgard.
When he was four (and already incredibly literate) he accidentally read a spell. "Jeg åpner mitt sinn til Thanos. Jeg aksepterer ham i. Jeg gir ham mitt sinn, kropp og sjel." (I open my mind to Thanos. I accept him in. I give him my mind, body, and soul.). From that day on Thanis was a constant presence in his mind, warping and twisting it to suit his needs.
When this was discovered- after Loki had tried to take Midgard- Odin was able to undo the spell, and Loki was free at last.
He decided that, in repentance for his damaging actions, he would live on Midgard and help protect it for the next 100 years. He moved into Stark Tower, and, eventually, Tony's bedroom.
Tony and Loki dated for 1 year, 3 months, and 18 days when Loki discovered, through a television report, that Tony was cheating on him. He confronted Tony, who confirmed this fact.
Loki left that day and ended up slamming into the one person who would help him, a woman named Ariel.
