"A lot of these problems are actually relatively easy to treat if you know how to evaluate them," said Goldstein, whose groundbreaking medical textbook, "Female Sexual Pain Disorders," was published earlier this year.
These problems are by no means rare. Goldstein said an astounding 20 million American women will suffer from sexual pain disorders at some point in their lives. Despite this prevalence, help for these disorders is still hard to find.
"I would say that probably only about 30 to 40 physicians in the United States really have extensive training in female sexual pain," Goldstein said.
This may explain the fact that the average woman with sex pain sees seven different doctors before she gets a diagnosis.
So what are the main causes of sex pain?
Perhaps ironically, the number one cause is birth control pills, Goldstein said. Birth control pills lower two hormones in the body -- estrogen and testosterone -- and that can lead to dryness and thinness in the vagina, which can lead to pain. For some women, that pain can be relieved by a simple adjustment to their birth control.
The second leading cause of sex pain is tight pelvic muscles, Goldstein said. In Fontaine's case, she received treatment with physical therapist Amy Stein, who she said helped her by stretching and strengthening her tight pelvic muscles.
"I tell patients that it's similar to neck pain, a neck spasm, but it's in the pelvic floor area and what we have to do is go in and lengthen the muscles," said Stein, who is one of a handful of physical therapists who specialize in sex pain and has written a book on the topic, "Heal Pelvic Pain."
Some doctors also use Botox injections to relax the pelvic muscles, allowing physical therapists to stretch them more easily.
According to Goldstein, the third leading cause of sex pain is an overabundance of nerve endings at the opening of the vagina. Though it's small, this postage stamp-sized area can generate a lot of pain, he said.
All three women -- Fontaine, Nugent and Veasley -- had this nerve problem. Fontaine said she found relief with some hormonal cream that soothed her nerve endings.
"I am able to have intercourse now, finally, and it's not painful," she said.
Nugent and Veasley both had minor procedures to remove the nerve endings. This simple, out-patient surgery -- known as a vestibulecyomy -- cures the problem in 90 percent of the women who have it.
Other causes of sex pain include endometriosis and skin diseases, Goldstein said.
Nugent said she is now happily remarried and, thanks to the surgery, was able to conceive and give birth this spring to a baby boy named James.
"It's important to get treatment and to talk to your doctor about it, but if your doctor doesn't believe you have a problem, then it's important to talk to someone who does understand the problem," she said.
Like Nugent, Veasley said she is deeply grateful that she found an answer to her problems.
"I feel fortunate to have found an answer for my pain, espcially because so many women do not," she said. "Those seven agonizing years compelled me to use my experience to help other women in pain."