What do i say?

My husband and I are separating. We’ve been separated for just over 2 months now. We have 2 kids together. Recently there have been a lot more “I’ve missed you” text from him. To which I don’t know how to respond. I don’t miss him. I am totally fine with getting along, co parenting and being friends/friendly. But I don’t want to feed into his text. How do I respond without having to sound rude ?