Ainz treated the ogMarchen and unborn child like a burden and indifference. He treated the MC Marchen like a nanny and housekeeper whom he later "respected" as...a friend.
Look I'm personally an ainz hater but If you think that how that part played out then it didn't really or a least not from how I interpreted it, from what I saw ainz saw it as his responsibility since he knew that it was also his doing for the child that enough is called respect as little as it seems. He still took responsibility, both merchan and ainz still respected each other being the reason why they lived their own life despite being married, at that time they respected each other as people or acquaintances, while at the end they respected each other as friends. As for the nanny part he didn't really ask merchan to take care of the twins? Our merchan just decided to take care of them on her own Accord and since ainz didn't really have a problem with it he just let her. But you don't really have to take my words for it I could technically be wrong since I stopped reading when I wrote my first comment
Ainz made the decision to take in the children before ogMarchen died and even told her (and she was horrified at how he could agree to that considering what she went through).
By taking in the children it meant he expected his wife to take care of them since he would not have the time to do it and it would be what was expected of his wife.
The fuck, y'all mean I've basically waisted an hour reading this..... also what the hell is up with her dying at the end like "oh you're done raising the children? Good! We don't need you anymore" like huh???? Why couldn't they just extend the story and let her find actual true love?? I'm ok if ainz and the fl just see each other as friends but the least you could do is let her hook up with someone who'll love her. Also can we just talk about how ianz is loosing friends left and right.... Boy lost his two best friends now he lost Marchen