There’s a startling gay secret reportedly behind the divorce of music’s beloved ’70s couple, CAPTAIN & TENNILLE!

After the singers’ 39-year marriage re­cently collapsed, the Internet lit up with claims that 73-year-old Toni Tennille dumped her ailing 71-year-old husband “Captain” Daryl Drag­on because she’s been seeing another woman.

One blogger insisted that the songbird “is gay and has had a girlfriend for years.”

Another online celebrity watcher, who said her information came from a friend of the performers’ family, added that Toni is happy with her lover and “no longer found Daryl useful, ever since his illnesses caused him to cease playing keyboard or performing music.”

As The ENQUIRER previously reported, Daryl suffers tremors caused by a neurological condition similar to Parkinson’s disease.

The entertainers – best known for their hits “Do That to Me One More Time,” “Muskrat Love” and the classic “Love Will Keep Us Together” – tied the knot in 1975, the same year they released their first album. They moved to Prescott, Ariz., in 2008, set up their dream home and antici­pated a happy retirement. The two later moved into a smaller place because, with Daryl’s health problems, “it became too difficult for them to take care of a bigger house,” said a source.

Up until now, there had been no in­dication Toni was hiding an alternative lifestyle. But during a 2007 press in­terview, she raised eyebrows when she stated the couple did not sleep together.

She was quoted as saying that their home had “two of everything. Two bathrooms, two bedrooms, two TVs… We’ve been doing that for 30 years.”

But Toni’s divorce papers – filed on Jan. 16 – state: “There is no reasonable prospect of reconciliation.”

A neighbor told The ENQUIRER: “Rumors abound around town that Toni might be gay. In fact, in all the years she’s been here, I’ve never seen her out and about with Daryl. It’s always been with a woman. Once I saw her at a Mexican restaurant, and she had her arm slung around the back of the chair of this attractive, younger blonde woman. I noticed she kept her arm in that position for most of the meal.”

The ENQUIRER attempted to speak with Toni – who is still living with Daryl – and to the lady that bloggers identified as Toni’s “other woman,” but both refused to comment.

However, Daryl – who is bedridden from the nerve disease and recovering from recent neck surgery – told The ENQUIRER he is devastated over the split.

“This divorce was Toni’s idea,” he said. “I can’t figure it out. She says she’s divorcing me for ‘spiritual reasons.’ But she also says over time her philosophi­cal beliefs have changed and that OUR values have changed. But she hasn’t been any clearer than that. Despite this, I still love Toni. We are not planning on selling the home, but things are changing by the day. It is frightening.”