FrostIron AU where Loki returns to New York (probably with Thor and Bruce?) and Loki and Tony form a relationship. Loki notices that whenever he uses his magic Tony gets uncomfortable. Loki thinks it’s because Tony doesn’t trust him, which is false, and Tony eventually tells him that since Wanda messed with his head he’s been paranoid of her powers and anything similar. Loki works with Tony to get over his paranoia and a few years later when Wanda tries to use her power to upset Tony he just shrugs it off and is like, “You don’t scare me anymore witch.”
Bonus: Loki shows Wanda what true magical power looks like, especially when she tries to use hers to harm Tony.