Partner doesn't believe in the mental load of mother hood

I'm a working (part time from home, kids are at home while we work we don't do daycare) mum of 2 kids under 4. my partner absolutely does not believe in the mental load or all the taks that come along with being a mother.

he refuses to believe it's real and it's really really upsetting to me because how can he empathise of support when he doesn't even believe what I'm struggling with is real.

how do I make him believe me ?

I don't feel very respected for my role in our family.