Feb. 1, 2013 -- The murder trial of Jodi Arias has been filled with salacious details of phone sex, graphic text messages, and an erotic sexual relationship between her and her devout Mormon ex-boyfriend, Travis Alexander.

Arias, 32, converted to Mormonism when she began to date Alexander, then 29, in 2006. Though they were both outwardly devout, they immediately developed a sexual relationship.

The trial has cast a spotlight on the tight-knit Mormon community in Mesa, Ariz., and its strict social mores, including a ban on premarital sex. According to Patrick Mason, a professor of religion who specializes in Mormon studies at Claremont Graduate University in California, the trial shows the difficulty Mormons face in coping wiith the church's demand for chastity.

"The LDS church puts a really high priority on complete chastity," Mason said. "They define that as no sexual relations of any kind outside of marriage between a man and a woman, no premarital sex and no extramarital sex either, and there's actually a lot of time and attention paid to this."

Arias is on trial for murdering Alexander, whom she dated for a year and then continued to have sex with for a year after that. Prosecutors allege she killed him in a fit of jealousy in June 2008, after taking graphic sexual photos with him and having sex earlier in the day.

Arias claims she shot and stabbed Alexander in self defense, and her attorneys have focused on Alexander's secret sex life as proof that he was a "sexual deviant" who was abusive and controlling toward Arias.They claim Alexander, who was considered a church elder, kept Arias his "dirty little secret" because sex outside of marriage was against church rules.

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See Jodi Arias Trial Videos More than anything, Mason said, this case shows the shockwaves sent through Arizona's Mormon community when those values were breached so flagrantly with a violent killing and the web of lies surrounding it. "Mesa is one of those concentrated areas of historic Mormon settlement."

"Were you shocked to learn (Alexander) was not a virgin?" defense attorney Jennifer Willmott asked Lisa Daidone, who dated Alexander after he broke up with Arias. Alexander and Arias continued to sleep together while he dated Daidone.

"Yes," Daidone said on the stand Wednesday. "I believed he was a virgin."

"Was Mr. Alexander living in accordance with his Mormon principles?" defense attorney Kirk Nurmi asked another witness, Daniel Freeman, a Mormon friend of Alexander's in Arizona.

"Yes," Freeman said on the stand Thursday.

"Was there any reason to believe Mr. Alexander was not living up to his Mormon principles as a church elder?"

"No," Freeman said.

Freeman said that Alexander never told him or other church members that he had a sexual relationship with Arias. In fact, Freeman's sister, Desiree Freeman, testified that Alexander made it known he was a virgin when in social settings, and "he joked about it."

The stakes are high for Mormons who choose to have sex, Mason said. They can face excommunication or a tarnished reputation among their closest friends and family members.

"In Mormonism, if you're not married, your social capital is largely defined by preserving your virginity. If it is known that you've had sex before marriage, even if people try to be compassionate and not judgmental, there is no doubt that in Mormon communities and the eyes of other Mormons... it lessens your social standing."

The conflict between Alexander's outer appearances and his secret sexual trysts with Arias is key to the defense's strategy of painting him as an abusive lover. But the testimony has also shown, conversely, how sexually conservative and pure many young Mormons in America are.

Arias Trial Shows Young Mormons' Sexual Self-Restraint

Daidone testified that she did not want to have sex with Alexander, or even make out with him in a passionate way because of her religion. She said she knew so little about sex at age 19, when she dated him, then when he got an erection, she told him he was thinking about sex too much.

"Actually what was going on was very normal affection, when he was kissing you, he achieved in erection, right?" prosecutor Juan Martinez asked Daidone. "It was a biological response to your lips, right? But because of your inexperience, you thought he should have controlled his penis from getting big just because he was kissing you, you thought that, it was because of your inexperience right?"

"Yes," Daidone said quietly.

According to Mason, Daidone' experience is typical of Mormon teenagers who do not get much in the way of sex education growing up in Mormon communities.

"A lot of Mormon teenagers don't get good sex education. Because of the priority the community places on chastity, which includes chastity in deed but also in word, Mormons don't talk much about sex. They are extremely circumspect about it," Mason said.

"A lot of Mormon teenagers, men and women, don't know much about sex, don't know how it works, they just know it is something they're not supposed to do, so they associate it with something dirty," he said. "Mormons have long debates about how far is too far. Some won't even kiss, and French kissing is usually seen as bad."

Ryan Burns, another Mormon who has testified at the trial, went on a date with Arias the day after she killed Alexander, though Burns had no idea about the killing. He hesitantly described a chaste date between the two, where he and Arias cuddled and kissed, but stopped before things went any farther.

"We went back to my house. We talked for awhile, and agreed that we were going to watch a movie. At some point we were talking and we kissed. Every time we started kissing it got a little more escalated. Our clothes never came off, but at some point she was kissing my neck, I was kissing hers, but our clothes never came off," he said.

Burns said that both he and Arias stopped kissing at the time, though they again became physically involved later in the evening when Arias climbed on top of Burns and began kissing him. Burns said that they stopped kissing because he did not want her to "regret the visit" because of her Mormon beliefs about sex.

"She would often tell me about how she felt about her religious beliefs, and we would talk about the Book of Mormon. That's why I didn't want her to regret her trip," Burns testified.