Oscars host Ellen Degeneres and her wife Portia de RossiReuters

A tell-all book about the romantic relationship between American talk show host/comedian Ellen DeGeneres and her wife actress Portia De Rossi is set to be published by September.

Celebrity journalist Randy Jernigan told Radar Online that his new book, The Life and Career of Ellen DeGeneres, will provide intimate details of the relationship between the most popular lesbian couple.

DeGeneres married the Australian-American actress in 2008. However, there have been several reports since 2013 that the couple's marriage was on shaky grounds.

"Many fans don't know that Ellen and Portia have had a very tumultuous romance since the very beginning," Jernigan told the website. He reportedly spoke with 13 of the Oscar host's friends and family members for the new book.

Meanwhile, Jernigan said the 41-year-old Ally McBeal star's low self-esteem is spoiling the couple's relationship.

"She loves attention because she's secretly so insecure," he said. "She also hates that her career is in the dumps."

In Touch magazine had recently reported that De Rossi entered rehab in May for 30 days to deal with apparent alcohol issues.

However, DeGeneres and De Rossi want to make their relationship work.

"They both care for each other very much," Jernigan added, "but neither is good at the whole give and take aspect of a relationship."

Amidst reports that their marriage is in trouble, DeGeneres told the People Magazine that her feelings for her partner grow stronger every day.

"I love her [Portia De Rossi] so much it kills me. The tabloids had a photo of Portia not wearing her wedding ring. It is because it gives her blister while riding horses," she said.