I worry about you starting to resent your girlfriend for getting to have all the fun.
I have a suggestion that might save your relationship or might strike you as all sorts of wrong and make you hate me, but here goes: You guys find a willing top, maybe somewhere in your social circle, maybe online or in a BDSM social organization, and bottom together sometimes. This kind of shared adventure can be hot, hot, hot and very bonding, sort of like getting lost in the woods together and surviving through mutual trust and interreliance — but a lot more fun. I think if you do that sometimes, and play top sometimes, and stick with the vanilla sometimes, you'll probably be OK, provided you both take care of getting your itches scratched. Love conquers ... much.
Andrea Nemerson has spent the last 14 years as a sex educator and an instructor of sex educators. Visit www.altsexcolumn.com to view her archived columns.