Discharge???

Ok I know this sounds stupid, but what exactly is discharge? I have had it my hole life and to be honest it's embarrassing. I'm married and my husband knows I have discharge ALL THE TIME. But he will do a load of laundry and be like "Damn babe your underwear are full today" I even wipe it out of my underwear during the day. I get all mad and upset cause it's embarrassing, he reassures me that it's no big deal he is married to me and he don't care, but it's like I'm very self conscience about it.