You can still have your clit played with, if you wear tampons.
Maybe him giving you a massage with some LH massage candles and then finishing him off with your hands, mouth etc
I second shower sex, if possible. Also, familiarize yourself with which days are your heavy flow days and which days are lighter and try to have sex on the lighter days if you're freaked out by blood. I tend to find that sex is good for cramps, especially any sex where I'm on top and have to move around a bit, so be creative and don't let a little blood get in the way of your sex. :)
You could wear a tampon and then get some of that massage stuff, cant remember its name but it was in the testers page recently, and then do full massages rubbing up against each other, kind of like dry humping. Maybe use a bullet vibe for clitoral stimulation, then finish him off by hand or mouth.
+1 on shower and anal sex. We also like to have bath sex when I'm on my period, you generally won't bleed when in water and if there is any blood its an easy clean up!