Jurors in a San Diego murder trial heard from the victim’s mistress, a woman in the center of what prosecutors call a deadly love triangle.
Jennifer Trayers is on trial, accused of stabbing her Navy doctor husband to death while he slept in their North Park condo in December 2010.
Prosecutors claim the defendant's planned the attack after discovering her husband’s extra-marital affair.
Defense attorneys say their client never planned to kill her husband and was trying to kill herself.
Mistress Testifies in Deadly Love Triangle
On Wednesday Navy doctor Danielle Robins spoke about her relationship with the victim, Lt. Commander Fred Trayers.
Trayers and Robins first met aboard a U.S. Navy hospital ship USNS Mercy in August 2010.
Weeks later, Robins said the two fell in love, but wouldn't have sex until Trayers left his wife Jennifer.
Woman Begins Trial as Murder Suspect
"So we kept boundaries,” she testified. “It would be kissing, holding hands cuddling, leaving it at that."
Robins says Trayers told her his wife had cheated on him in the past and was debating on whether to end the marriage.
Robins says she suggested marriage counseling, but claims Trayers wanted to move on.
"He expressed a lot of excitement,” she said. “He seemed to be eager to have a future with me."
A week before Trayer's death, Danielle testified that Jennifer Trayers announced she was pregnant. Robins said she made the decision to end the affair and told Fred Trayers it was over.
"I felt like he was obligated, if she was pregnant, to stay with her," Robins said.
Robins said Trayers gave his wife an option.
"He told her, he had been planning to leave but If she wanted him to stay for the baby, that he would," she said.
On the day Fred Trayers was stabbed to death inside his North Park home, Robins said she got an eight-page email from Jennifer Trayers.
The email talked about how much Jennifer Trayers loved her husband and how she was there for him for 19 years, even when she claims he had cheated on her with other women before.
Defense attorneys told jurors the evidence will show their client is guilty of involuntary manslaughter not of murder.
"She took the knife as they were wrestling over it away from Mr. Trayers and just started stabbing him," Kerry Armstrong said in opening statements.
Armstrong said Trayers did have self-inflicted wounds to her chest and torso. He also said Trayers will testify during the trial.
Fred Trayers worked as an emergency room physician at Naval Medical Center San Diego at the time of his death.
If convicted, Jennifer Trayers faces 26 years to life in prison.
Keep up to date on breaking news: Download our improved iPhone app, follow us on Twitter @nbcsandiego, fan us on Facebook, sign up for our breaking news e-mail alerts or text SDBREAKING to 622339 to receive text messages for local breaking news. (For more info, text HELP. To end, text STOP. Message and data rates may apply.)