What is it like when your breasts start leaking?

My husband and I just had sex... About 30 minutes afterwards, I notice my breasts feels wet. I thought maybe he sucked on it, so I just wiped it off, and ignored it. Well now it's wet again. It's really thin and slippery. I wiped most of it off while putting on a shirt. And my nipple is a little tender. Husband said he didn't suck my nipple or anything .... I am 31 weeks