To be fair to the uke the seme is a total jerk in the beginning, as well. I mean the way he just selfishly says "you're an omega, you need to understand that" is so careless. Also, there was a comment above yours that puts why the omega acts the way he acts into perspective. Basically, they said the omega never had good parental figures, so it's a little insane that we're expecting him to be a good parent right off the bat.
Honestly I think how he acts is due to his own past traumas. Like his own father sold his wife to other alphas, he dropped out of high school out of fear of being sexually used, his mother abandoned him with his abusive father, and he had to survive as an omega-looking alpha at 17/18 without any plan or support. When the seme and uke met up, he was already 20/21, so it’s been like 3 years. He never lived a “true childhood” and always felt useless (and even hid his own abilities, like math).
All of the trauma from parents who didn't act in his best interest shaped him with fear. This was one of the main reasons he was scared throughout the entire pregnancy. For example, the scene where he felt his child kick set the the fact that he would be a parent in. All of the pain and misconceptions of being a parent and being married continued taunting him into his adulthood. So even though he does act like a jerk and pretty selfishly, it’s like he’s trying to compensate or cope with his pain. All of his desires for gifts and money could be due to his childhood and when he was alone and dropped out of school.
Sorry this was long. I just wanted to get across my thoughts without confusion haha.
Honestly, the uke is such a jerk I hate him. He’s selfish and inconsiderate CONSTANTLY. BUT I LOVE THE STORY SO MUCH