(CNN) -- Howard Selekman knew he had been attracted to men since he was 8, but in his 20s he still planned to marry a woman and have children with her. When he brought his fiancee to see his psychiatrist, the young woman was optimistic, even though she knew Selekman was gay.
"My wife-to-be said, 'I think love will overcome the obstacles,' " he said. "And I will never forget my psychiatrist saying, 'No, it will not overcome all of the obstacles.' "
The next 36 years would prove his psychiatrist right -- Selekman never overcame his feelings that indicated he was gay. This year, at age 61, he finally divulged his sexual identity to his brothers, and "went public" through sharing his story on CNN's iReport.
Marrying someone of the opposite sex, but coming out as gay or lesbian later in life is not uncommon, therapists say. A prominent example is actress Meredith Baxter, 62, who had been married to men three times but recently announced that she has been dating women for the past seven years. The thought of being gay "had never crossed my mind," before seven years ago, she told People magazine earlier this month.
Watch Howard Selekman tell his story
Video: Coming out late in life
Women, more often than men, report having these awakenings later in life, said Chris Kraft, clinical director at the Johns Hopkins Sexual Behaviors Consultation Unit. Males who decide to adopt a gay lifestyle late in adulthood generally have known about their orientation since their school years but do not want to risk telling others, he said.
iReport: Everyone's time table is unique
It's hard to say what it means to "not know" that you are gay until late in adulthood, said Gail Wyatt, sex therapist and professor at the University of California, Los Angeles. But she and Kraft both know of people who simply did not know how to interpret their feelings of attraction for many years.
Read more iReports about coming out
Generally, sexual orientation becomes apparent to a person in adolescence, and to boys slightly earlier than girls, experts say. But sometimes the feelings of arousal and excitement that come from members of the same sex, even from casual sexual encounters, may feel more like "risk taking," and don't prompt a person to embrace a new sexual identity, Wyatt said.
"They may have kids and families, a life that they would have to change, and many people don't want to have to make that kind of change," she said.
Growing up, Selekman, now a retired teacher in Pittsburgh, Pennsylvania, said his father physically brutalized him, and was even harder on the two older brothers next in age when they didn't do typical boy activities. One of the brothers liked to dance and would run around with his hands in the breeze, and the father hated that his sons were "a bunch of sissies," Selekman said.
The younger of those two brothers married and had children, but came out in his 30s. The older one went down a "dark path" with his gay identity, and died this year, Selekman said.
Science has not homed in on a single cause for homosexuality, but research has found various genetic associations in males. Studies have found that having older brothers increases a man's likelihood of being gay, as well as that the arrangement of a mother's genes could impact whether her son is gay. A study on identical male twins found that if one twin was gay, the other had a 50 percent likelihood of also being gay.
No genetic factors for females have been found, and no environmental associations have been identified for either gender, Kraft said. Still, many experts assert, it's obvious that sexual orientation is not a choice, if only because no one would choose a lifestyle so highly stigmatized.
Wyatt and Kraft both strongly believe that a person's sexual orientation cannot be changed through counseling or therapy.
"If something feels good to you, there isn't anybody who can persuade you differently," Wyatt said.
Selekman had plenty of temptations to leave his wife for men. Even on his honeymoon, a man approached him while his wife stepped away.
But Selekman stuck with his marriage, and dared not tell anyone about his homosexual desires. At the school where he taught, he didn't socialize with anyone beyond the required meetings, keeping as low a profile as he could.
Still, his passion for teaching -- as a child, he would ask for blackboards and teacher's editions of textbooks for birthdays -- paid off. In 1990, he was named Pennsylvania's Teacher of the Year for his role as an eighth-grade English teacher and took on leadership positions in education committees.
In having his own children, now 29 and 31, he and his wife did share happiness, he said.
"The years we were rearing our children, because we had these two wonderful children, we were unified in loving them," he said. "We were doing the best we could by them, there was great happiness and great joy."
But not long after the second child was born, Selekman felt a dramatic physical separation from his wife. He no longer wanted to be touched, and the two had separate bedrooms nearly 10 years ago.
Selekman went back into therapy, but the therapist did not help with the issue of gay identity, and later Selekman suspected homophobia was at play. In the last two years of their sessions, Selekman found himself crying after every appointment, he said.
The breaking point came this summer when one of Selekman's gay brothers died, having had hepatitis C and lung cancer. Selekman finally shared with his surviving brothers -- one gay, one straight -- that he too was gay.
They encouraged him to stop seeing his therapist and find a different professional who could talk with Selekman about his sexuality. He has since been seeing a therapist with a mental health outreach program for gays, lesbians, bisexuals and transgendered individuals, and finds this a much better fit.
Divorce isn't always the solution for gays, lesbians, bisexuals and the transgendered who are in heterosexual marriages, therapists said. Some couples choose to stay together because they don't want to disrupt their children's lives. But others separate and successfully begin new lives, Kraft said.
"I tell them to really be careful and consider all the people involved" when choosing if and how to come out, he said.
Selekman's wife has been frightened and angry since his coming out, he said, and he is not certain what will happen with their marriage. But they are still living together in the same house in Pittsburgh -- neither wants to deal with financial hassles, he said -- although his wife has said she is considering moving out.
CNN could not reach his wife for comment.
"We are like two strangers passing in the night," he said. "I didn't lie to her. What she wasn't counting on was that love did not conquer all obstacles, so there's quite a bit of tension between the two of us."
There are some people who come out and regret having done so because of the stigma and lack of understanding of those around them, but worse is when a spouse discovers it through porn, Web sites or evidence of an affair, Kraft said.
"We're careful to not say to people, 'Come out immediately' -- that's not realistic," Kraft said.
For someone who has decided to date members of the same gender, there's a whole process of socialization that has to be learned -- a lot of people don't know how to establish a same-sex relationship, Wyatt said.
"Just like the first date, the first kiss -- it's still a first," she said. "There is learning that has to take place, and certainly learning in a safe way so that disease does not get transmitted, so that people get tested, all of those things have to come into any kind of relationship today."
It has taken Selekman decades to come out, but he is hopeful about the future. He is feeling lonely, but has plans to volunteer with an LGBT organization and attend social group meetings, in addition to his current volunteer role as supervisor for student teachers and teaching interns at the University of Pittsburgh's School of Education.
"My one wish, and it hasn't been fulfilled yet, is to have some gay friends," he said.
