Baby fever/relationship situation

Hello I only have a son the guy I have been dating for awhile we talk about kids but now if I say anything about kids he change the subject or act like he don’t hear my he has 2 kids 2 boys he always talks about he wants a girl but now he just doesn’t like the talks anymore I want another kid and I think he has mix feelings but it’s kind of distance in our home now because of it I don’t know what to do anymore I just really don’t say anything to him anymore about kids or being romantic or anything about our relationship