Yeah. I saw that as well. But I had a feeling it was gonna lead to another kid. He wants to be part of his kid's life at least. And Noah as well if he wants more kids. If not then they can just amicably co-parent. Also, Ian would now have to live in Korea but he would have to adapt since he was raised abroad.
I can only see him trying to impregnant Noah intentionally to tie him down more, or after they get their happily ever after. He wants Noah. He's not letting him go. He wanted him when he was a beta and even bettter that he's his omega now. He's just in his seme ignorant phase like much of other bl plots. They were pretty much together in college but Ian just didn't want to admit to commit. I'm telling ya, the dropping of the inhibitor was intentional! We're gonna get flashbacks of the semes viewpoint down the line! Mark my words! XD And if I'm wrong you can say so once the story ends too lol.
I think the seme intentionally dropped the blocker so the uke would give it back to him.
Judging from the dialogue it really didn't seem like the seme knew the uke was a recessive omega. I don't know if the author is going to go the whole 'fated mate' match route, but at the very least I think because the seme was a dominant alpha, he could've probably sense the ukes recessive genes and was extra attracted to him cause of that as well.