saw these tags from @the-piper-and-the-lion and I want to give my two cents, but I also suspected it would get long.

I think you've hit the nail on the head for Robin, and my theory is there is a very similar explanation for Andrew. Robin was spoiled growing up, the golden child, very young and relatively sheltered, and had someone who catered to her every need and want. This is what she brings in with her to her marriage.

So, what about Andrew? Well, I think the answer is in a line from Aunt Irene: "I've always been more like a mother to him than a sister." As others have pointed out, we get very little insight into Andrew and Irene's life, but what is made repeatedly clear is that Irene is to Andrew what the Grandmother is to Robin. It manifests in a different yet (almost) equally insidious form.

Andrew is selfish, has been petted over his entire life, has also had his every need and wanted catered to, and really could also be seen as the golden child as well. This is what he brings in with him to his marriage. As you indicate, the war trauma also plays a huge role here in my opinion. I don't think Andrew was exaggerating when he talked about his first impression of Robin, despite the flowery language. He was desperately grasping onto anything that was not the war, specifically anything that was the opposite of blood and filth of the war, and one of the first people he sees? Robin.

Andrew's deal is that he did not understand that he was marrying a person in her own right. He was marrying an escape route. This is not to say that Andrew was not actually in love with Robin; it's more to say he saw all the shiny parts of her - and that was it.

So you take that, and you combine it with what Andrew is bringing to the marriage - selfishness and unreasonable expectations - and you combine it with what Robin is bringing to the marriage - naivety and unreasonable expectations - and you get one hot mess. Both Andrew and Robin were taught what love is like by Aunt Irene and the grandmother, respectively. Andrew seems to be more well-rounded in his views because he wasn't as sheltered as Robin, but at heart that influence is there.

Robin is described as spoiled, but what's unstated is that Andrew was too. It's implied in almost everything he does. He expects his marriage to be about him. He expects Robin to focus on him. Of course he's going to be mad about a baby; it means he's not the center of attention anymore. On top of that, if we want to leap into more speculative territory, we also have his reaction by seeing the medal from the war over a decade later; I can only imagine what living with him must have been like when he was fresh off the battlefield and beginning to really grapple with what he'd seen.

And, very importantly, in the midst of this hot mess, in the midst of everything crashing down, you have Aunt Irene. She's picking apart Robin - and she's definitely affirming Andrew. Yes, Robin is being unreasonable. Yes, she's being hysterical about Jane's health. Yes, she's spending too much time with her baby; good thing I was there to help get supper on the table. She's fanning the flames of Andrew's pride and driving every wedge she can find between him and his family.

This is not at all to excuse Andrew's behavior here. He should have been capable of taking that millimeter step of recognizing Irene's toxicity, but he likes that Irene affirms him and pets over him, and his self-centeredness blinds him. It blinds him, and in the end, it costs him everything.

As for who Andrew is...I think Andrew was the cocky, confident man in uniform who was charming and knew it. He also wasn't just a blowhard; he was intelligent and sharp. He writes political commentary and gets along well with everyone. He's shown to be a pretty outgoing, hotheaded, arrogant dude who is more than a little stubborn (he did stay up arguing with his friend until the wee hours of the morning). He's seen things he can't forget and that he'll always carry with him. He's spoiled. His ego is massive. He's friends with everyone from fellow political commentators to the Jimmy Johns.

You're right in that we only ever see Andrew through Jane's perspective, but we do get the bare threads of who he is outside of "dad." Someone struggling with PTSD, someone so arrogant he can't-or won't- see what's in front of his face, someone who spends time advocating for international peace, someone who snaps savagely at his friends in arguments, someone willing to stay up all night for those arguments, someone who is a keen learner, someone who seems so ashamed of his behavior he doesn't want to be called father, someone so arrogant and ashamed at the same time he thinks Jane hates him even after he has met her and doesn't expect her to want to return - it's barely there, but it's there. I'll end this long post by saying i would have killed for an andrew/robin perspective or prequel or sequel lol.