A brief search of the net finds a support group for men married to lesbian or bisexual women on Yahoo. They refer to your situation as a Mixed orientation marriage.
http://groups.yahoo.com/group/MMTL/
I think there are a lot of other sites both on lesbian sites and something called straightspouses.

I know my mother joined a support group when I was 12 called Spatula. I asked her why that name and she said because parents flip out when they find out their kid's are gay.
Unlike our very, very wise friend, StubbornDyke, I am bisexual and so cannot imagine ( I have tried) having feelings exclusively for one sex. So, it is very hard for me to imagine what your wife may be going through, and like StubbornDyke, I always knew my orientation. I was trying to imagine just waking up sometime in mid life with an understanding that I was a lesbian when I had always thought of myself as straight. I hear a lot of love in your writing. Lots of concern for her feelings and her struggles. Some relationships...The Course In Miracles would call them holy relationships, transend the physical.
Many issues for you two on the road ahead. All that love is going to help.
desdamona


Arguing with reality is like trying to teach a cat to bark—hopeless. (Byron Katie)