Lichen Simplex and Sex

I've been dealing with Lichen Simplex Chronicus for over a year now.
I have it on my vulva, below the vaginal opening.
It showed up about 6 months into my current relationship, and I think it's caused by sex.
He is big, and I'm little, therefore there is alot of friction down there. I think that's what is causing the constant irritation.
The thing is..I use the topical steriods almost every day, and it seems like I'm suffering from the irritation every day.
Usually it flares up almost immediately after sex and can last from a couple days to over a week...and by then, we've had sex again, and it just continues the cycle of irritation, itching, burning.
The skin gets red and puffed up, and what looks like tiny little stretch marks, are actually breaks in the skin.
I'm just so sick of dealing with it.
We use lube, try to extend foreplay and all that, but still every time I end up in pain.
And the topical steroid cream stings when I put it on! Is that normal?
My doctor doesn't have much else to offer besides: lube and the steroid cream.
It just never stops or gets better.