He hates me and why do I care?

I don't know where to even start. The OW befriended me after I cold busted him cheating on me. She would text me every day wanting to know how I was doing etc. However these past few days she's been short and abrupt with me and I'm like WTH??? Why act like you wanted to be my friend? Was it to keep tabs on me to make sure I wasn't going back to him? Why do I care? But I do. It hurts and makes me sad that yet another person has used me and I feel so dumb for trusting someone especially the OW. I miss him and I'm sad and I'm lonely. That's all. Just wanted to share.