2 Works by letmeinthewallsyouvebuiltaround in Teen Wolf (TV)
Stiles meets an aggravating-turned-friend strawberry-blonde at college who ends up turning his world upside down, but it's nothing compared to the whirlwind that occurs in Lydia's life when his world collides with hers. Slow burn Stydia AU. Multichapter. Also can be found on fanfiction and tumblr.
Post 5x05. Lydia catches on that something is going on with Stiles. She thinks she has a pretty good idea what it is too, so after a pack meeting, she confronts him. Stiles ends up confessing what happened with Donovan.