I think they ask about kids in the interviews and I have no idea what the answers were.
Yes, Matt has been distant but, I'm not sure which came first, him pulling away or Amber overreacting to things like him going to the guest bathroom because my first inklings of his distance was in scenes where she wasn't onscreen.
Based on what I have seen, reassuring Amber about her fertility probably wouldn't have worked. For example, her conversation with her sister was all about Matt being the "old dad" not Amber's egg quality.
Full disclosure, I agree with Matt's position on once you have children, that person is there forever. That is one of the reasons I was using multiple forms of birth control before I got married. I also confessed to having some anxiety once I was married, pregnant and starting to show because of the realization, "Now I'm in this for real. There is no way out even if we divorce. I have to maintain a relationship with my husband for parenting no matter what." We were and are happily married but, the anxiety was real.
To your point about the experts, I wonder if they do call but, the footage hasn't been shown. That's dumb if it's true. I'm just speculating.
I don't think Matt (or anyone) staying out all night without checking in is okay. But, it's also not a sign of emotional health to just repeatedly call a person who does not want to communicate with you to try and force it. It boils down to Amber's reaction being so exaggerated that it mutes some of the damage Matt is inflicting. I agree with you that he should have texted, I'm just not sure he didn't.