Why do I get itchy red bumps after sex?

I've only slept with one guy my whole life. Each time after we have sex, I develop these red itchy bumps all over my body. They itch 24/7, I even wake up in the middle of the night scratching myself. As a result of these bumps, I have scabs and scratches all over my body. I'm even developing random bruises and muscle pain. Everyone I know is normal after sex. Did I catch something? Help!!

How long have you been having sex with this guy?     Does he use a condom?  My first thought is you may be allergic to the latex in a condom, or to a lubricant or a spermicide. My second thought is maybe you have an allergy to his semen. This is rare but it can happen.     As you are developing bruises and muscle pain you should see your doctor.  

We don't use condoms.

Did you ever find out what was causing your itchy bumps?   It could it be histamine release caused by sex hormones. How long does the rash last?    Have you tried taking an anti histamine tablet after sex?