Will guys think having a dark thigh interior ??

The skin down by your vagina is different and does change. Some women are darker than others. Go and get a book called Petals, which is a pictorial book of nothing but women's vulva's. You will see a wide variety and each one is different, unique, and beautiful.

If he is turned off or thinks that it has anything to do with your sex drive means he doesn't know what he is talking about.

That's not really what I'm looking at. But yes there are girls who are darker in color there. It's just the way mother nature made you. Some have bigger nipples than others. Some darker & some lighter

Thats not a big deal really. I have a line (yeah a visible line) down from my neck to my "flower" (I'll just call it that) that is perfectly between both halves of my body. So its light on one side, and really tan on the other (and no, I don't sunbathe) My guy thinks its really weird, but it doesn't make you a freak. It won't turn him off. He would be there for you, not your thigh.

Dark inner thighs are very common. It's caused by natural pigmentation of the skin and genitals are often a different colour to the rest of the skin.

Your boyfriend shouldn't assume anything about you based on the colour of the skin in that area because it simply isn't true.