Limerence is holding me back from taking dates seriously

I went on a date for the first time in a while, and I actually really liked the person I met. But somehow my LO came up in conversation, and I felt immediate sadness talking about him. I'm not sure how long I'll have to grieve this. I hate how hard it is for me to move on. Even writing this is making me tear up. I'm really pathetic. I almost feel like I'm betraying him by trying to care about someone else, even though we were strictly platonic.

I wish I could just be present with this new person. Instead I feel a heavy sense of loss that's been plaguing me for a while. I can't be a normal person who moves on when a relationship isn't possible. I wish I didn't feel everything so strongly.