Guy friend lately has been ignoring my messages for hours?

I'm 27, guy friend (41) lately leaves me on read or doesn't read them for hours and sometimes we talk about fertility or politics, I did mention that I was dating someone but I have this gut feeling that my he likes me. A couple years ago he did flirt with me, but i don't understand why he pulls back after we have personal conversations, he also wants me to stay single for awhile plus I have been posting more selfies on fb and that's when he started being like this as well, I don't understand why he is like this

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When I said we talked about fertility he was the one that brought it up and he brings up my hormones
Guy friend lately has been ignoring my messages for hours?
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