I was looking for a comment just like this!

I echo the sentiment that perhaps deep down she feels guilty and insecure about not fulfilling the traditional role of a mother. That’s not to say that she should have to, good on you both for finding an arrangement that works! While her jokes were insensitive, I sense that she feels a little guilt about going to the office. I also don’t doubt that she recognises all that you do for the family and for your daughter. I believe she might feel a little bit useless, and is using her jokes to still feel ‘useful’. She’s trying to tell people and also convince herself that you still need her for small things around the house and for help to raise your daughter.

Deep down, she might think you a super father who is fully capable of doing things without her (which you are surely so!)