(San Francisco) Wah Cheong, a lifelong Republican and the soon-to-be divorced father of two teenage boys, sometimes surprises his co-workers and neighbors in a relatively conservative community outside San Francisco when he says he supports same-sex marriage.

Silence usually follows. Then, a spark of understanding.

Of all the constituency groups that advocate allowing gay couples to wed, none is perhaps more counterintuitive than the heterosexual spouses of gay men and lesbians.

Yet as the issue plays out in the nation’s courtrooms and statehouses, some of the wives and husbands who learned that their partner was attracted to other women or men are making their voices known in the often-polarized debate.

“We are the unacknowledged victims of the victims of homophobia,” said Amity Pierce Buxton, the founder of the Straight Spouse Network, a New Jersey-based support and advocacy group with 52 U.S. chapters. “When gays and lesbians feel they have to get married to be accepted and to have kids, that hurts not only gays and lesbians, but straight spouses and kids.”

The board of the volunteer-run organization, which claims thousands of participants, has adopted a policy of opposing laws that limit marriage to a man and a woman. Last fall, as California voters considered whether to amend the state Constitution to outlaw same-sex marriages, Buxton, 80, who lives in Oakland, wrote an impassioned opinion piece arguing against Proposition 8.

Some network participants have marched in gay pride parades, tried to persuade church groups that the Bible should not be used to justify anti-gay attitudes, and met with groups of gay fathers struggling to stay on good terms with their ex-wives. Others have expressed their views on talk shows when married politicians like former New Jersey Gov. Jim McGreevey come out or are outed, or just quietly shared their perspectives in hope of changing a few minds.

To be sure, not all mates who discover they are in what has become known as “mixed-orientation marriages” are so sanguine. Cheong, who was married for more than 17 years when his wife told him she thought she was a lesbian, said he knows other straight spouses who voted for California’s same-sex marriage ban “out of spite for their ex’s, nothing else.”

Regardless of where they are on the acceptance scale, each spouse can pinpoint devastating moments of discovery or disclosure that rendered their marital relationships unrecognizable, if not shattered.

For Carolyn Sega Lowengart, 61, who lives outside Washington, D.C., it came after 31 years of marriage. Lowengart thinks if her husband had not seen his sexual orientation as a stigma, both of them would have been free to pursue other relationships.

After her husband moved out, “I asked him, ‘When did you know’”‘ He said, ‘When I was a teenager.’ I said, ‘Why did you marry me?’ And he said, ‘Because I didn’t want to be (gay),’” she said.

Randy Spires, 59, a former military police officer who lives in Southern Maryland, said he went through it on his 21st wedding anniversary when he found an e-mail his wife had sent to her female lover. Compounding his anger and confusion were the reactions of straight male friends who joked that Spires was lucky to be married to a lesbian.

“I’ve always compared the straight spouses with a chalk line at a crime scene,” said Spires. “The gay and lesbian community doesn’t want to associate with us because they think we are angry or what do you have to worry about, you’re straight. And then you have the heterosexual side saying wait a minute, there must be something wrong with you for this to happen. We lose our own identity. We don’t have a face.”

Spires’ ex-wife, Sue Spires, says she regrets having hurt Randy but does not completely understand why, 13 years later, he feels a need to talk about the end of their marriage, which produced two sons. But she agrees with him that if same-sex relationships had been more accepted when they were young, she would have had a relationship with a woman.

“I knew I was gay from the time I was 8-years-old,” she said. “But the socially correct thing to do was to get married. That’s what I did. We didn’t have an unhappy marriage, but if I could do it again I would be able to tell him, ‘No, I’m sorry, I can’t go through with this.”

Buxton, whose 1991 book, “The Other Side of the Closet,” is considered the definitive work on the topic, estimates there are as many as 2 million gay men and lesbians in the United States are or have been in heterosexual marriages. About seven out of every 10 involve women married to gay men, she said.

Of those who contact the Straight Spouse Network – the organization hears from five new straight spouses a day – about one-third immediately split up when the gay partner comes out. Another third stay together for a year or two. The remaining third resolve to make their marriages work.

Citrus Heights, Calif. residents Jim and Anne Marie Will are in the last category. Former high school sweethearts, they had been together for 15 years and married for 11 years when Jim told his wife in 2001 that he thought he was gay but had never acted on his feelings.

The couple, who have a 16-year-old daughter, decided to stay together and to give both of them the option to pursue sexual relationships outside the marriage, which Jim Will has done. Yet the bond between them remains strong, if unconventional.

When asked why they have remained married, both spouses say there is no one else with whom they would rather share their lives.

“Being open and honest relieved my burden of guilt and we were able to consider ways to safely accommodate my additional desires. There continues to be no one else we want to have a life with,” Jim Hill said.

“The one thing I have asked him to do for me is to not hook up with other gay married men,” Anne Marie Hill said. “I have seen the devastation these women have gone through, and I don’t want him to be part of that.”