Taylor Lianne Chandler, 41, who identifies as intersex, meaning she has male genitalia but no testicles, a uterus but no ovaries, has also shared intimate details of their alleged relationship via Facebook.

"I was never a man, never lived as a man. No one can say they knew me as a man or produce a photo of me as a man," she wrote.

"There are people that remember me as an androgynous child at times because of what was forced upon me."

Chandler said she was named David Roy Finch at birth and began taking testosterone blockers as a teenager before changing her name. She also underwent corrective surgery in her 20s.

Chandler said she met 29-year-old Phelps via Tinder before the most decorated Olympian of all time was suspended from swimming after being arrested for driving under the influence in September.

"Spending time with him was like a teenage love affair. I have never felt so comfortable and accepted in every way as I did with him," she wrote.

"I can't remember a time in my life where I didn't feel like I needed validation. The more I let go, the more I realise I don't need it from anyone. One man saw me for the first time in my life not for being different but for being whole. If you can't understand that, don't want to believe me or think my relationship isn't real, you can go f--- yourself!" she wrote.

The Washington DC based Chandler also told the National Enquirer the pair attended a football match for their first date and had sex during the half-time entertainment.

Chandler's social media presence is a virtual shrine to the swimmer where she regularly posts photos, updates about his condition and any press coverage their relationship attracts.

She has also been in trouble with the law and spent 30 days in prison for extortion.

"At 19 I thought it would be smart to blackmail someone into giving me the money for my surgery. As soon as I received the money I was arrested and charged with extortion," she wrote.

"I spent 30 days in jail because I was too ashamed to tell my family what happened, thinking no one knew. Even though my birth certificate and driver's licence said female they put me in a cell with three men and I was raped."

She now dedicates much of her time crusading for gender rights and is concerned her speaking out may signal the end of their liaison.

"I am probably going to lose him because he is a brand that his team wants to protect and things since he went to rehab came to my attention that didn't put him or our relationship in the best light," she wrote.

Phelps, who was previously suspended from swimming in 2009 after being photographed smoking marijuana, has yet to confirm the relationship with Chandler.

He previously dated another blonde woman, Megan Rossee, for 10 months in 2012 but reportedly split with the 25-year-old model as he wasn't happy with her broadcasting aspects of their relationship on social media.