Me and DP had this conversation a good few years ago, however it went a bit differently for her.
We've always been fairly even with most housework, do around the same amount even if some jobs were hers and some mine, so shes the only one who dusts, and I'm the one who cooks etc.
But I'll admit that most of the stuff to do with school, kids activities, kids haircuts, clothes etc. fell to her, as a holdover from when she didn't work.
We had a conversation about it, and I agreed to do more, but said that in return she needed to be more involved in things like DIY, sorting the MOT, insurance renewals, changing broadband deals, researching holidays etc.
We agreed what we thought was fair, she lasted a month before she was begging to go back to the previous arrangement.
Sometimes the mental load really is all on one person and needs rectifying, but sometimes couples take on different areas of it, and don't see what the other half is doing until they have to get involved.