I accidentally found out my two friends have been secretly dating and now I wish I didn't know

Two people in my friend group have spent the last YEAR insisting they absolutely cannot stand each other. Like actual arguments, constant roasting, “I would rather die than date them” type comments. Last week I accidentally saw a notification on one of their phones and it was literally “Love you ❤️” from the other person. I thought it was a joke until I started noticing everything. They disappear at the same time, suddenly have the same inside jokes, and somehow always know where the other one is. I asked one of our mutual friends and apparently everyone already knew except me. Then yesterday I watched them leave together and the guy literally looked around before holding her hand. I don't even know why I'm this invested but I feel personally betrayed that they managed to hide an entire relationship from me for months 😭