What is this?

Sometimes I get a small rash like this in the crease of my right thigh. It's not an STD. I was pregnant two months ago and they would have picked anything up from all the swabs I had because I've had this before I was pregnant and my husband has hardly enough time to have sex with me let alone anyone else seeing as he works 12 hour shifts and is constantly in pain from an accident he had years ago. It itches sometimes but usually doesn't. I am obese so it could be friction of skin on skin or skin on clothes, but I just wanted someone else's opinion.