My ex is dating my crush?!

My ex and I have broken up for almost a year now. He did it via text message and as you can imagine it didn't end pretty well. Fast forward to Oct, he and I patched up and we became "Facebook friends". I met my crush through Grindr and we hooked up at an event in August. It was seemingly going pretty well until he starting become unresponsive and ghosted on me. I was planning on asking him out a month ago but my friend suggested waiting for him to post on Instagram and "slide into his dm" so I won't seem desperate. Today he posted an insta-story and I opened it, all buttered up and ready to slide all the way into his dm, BUT IT WAS A DATE WITH MY EX.