S/O and Discharge

I've been with my boyfriend for almost three years now. We've both lost our virginity to each other and have come quite close over the years. I tend to get on his nerves a lot because I tease him constantly and find it hilarious because my sex drive is naturally higher than his, but he still loves me. But here's my predicament:

We've only had sex twice after losing our virginity because I'm terrified of the stains my discharge leaves in my underwear. Plus, every time I wear a panty liner he thinks I'm on my period.

What do I do?