Advice Please - My Boyfriend Just Told Me I'm Boring In Bed

I caught my boyfriend searching on Google '"My girlfriend is so boring in bed. How
do I tell her?"
So I asked him what's up and he, pomp and plain, told me he is not satisfied with
our sex life.
I can't even tell you how much of a blow that was to me. I was absolutely gutted.
I didn't even know whether to cry or beg him.
I know I'm not the prettiest girl in town and I don't feel comfortable flirting
around, or things like that.
But I know I'm a very good girl, I try!!
What the hell can make someone not boring in bed? What can I do now?