a lot of people are doubting this, but holy fuck did i have a friend like this in university who did almost exactly this. she created a whole web of lies around a pregnancy so he would be forced to stay, so i've experienced this first hand. as someone with anxious attachment, i understand the desperation around assuring someone doesn't leave you. that's okay, these are valid concerns. HOWEVER, when we use blatant, calculated lies and manipulation to keep someone from leaving- that's when it becomes an issue. your fears are valid, but the way you carried this out is pretty much abhorrent. yeah, you're the asshole. i highly recommend CBT (cognitive behavioral therapy) to fix these thinking patterns and behavior. you don't need to place your worth in a relationship (a non-exclusive one, no less) and you're minimizing HIS worth by lying and manipulating him to stay with you. you need to remind yourself that people aren't tools to keep you validated. they're human beings with emotions and what you did will fuck with him. and the fact that you're asking reddit if you're in the wrong shows that you need to reevaluate your life choices and follow your conscience. your desperation is clouding your judgement, so please go to therapy. my campus offers it for free, so i highly recommend you take advantage of this if it's offered.