User blog comment:Kaido King of the Beasts/Chapter 892: The Translation Where Chopper Says "STFU"/@comment-81.162.199.242-20180127182622/@comment-53539-20180131125139

Based on Pound, Big Mom tosses aside the fathers aside after they have given Big Mom want she want, as they aren't considered family. Big Mom only considers her children family, likewise they only consider her and each ther family. All father-in-laws and son-in-laws/daughters-in-laws are unrelated to her, simple as that.

Its worth noting that despite the fact the children do not see the husbands as family or any of the arranged marriages, the children married to their spouses still love their partners and consider them their family.

I doubt many of the father's are around and all have been sent away or dealt with like Pound was.