As a mother, I can definitely understand the insecurity Theo is feeling about the changes happening with his body. I'm sure it's worse for him because he is man. But he shouldn't, its part of being a parent. I am very lucky to have a husband who REALLY loved the way I looked when I was prego. And Theo is just as lucky!
If only the king, the uke's dad, would find out that his son is an omega! That would solve everything. He would marry him off to the seme in an instant. Because his omega son would be able to continue his family line and do it with his favorite general. The biatch mother knows that, and that is the real reason why she is hiding the fact that he uke is an omega.