David Foster won’t say why he divorced fourth wife Yolanda Hadid, but insists it had nothing to do with her illness.

When the two split in 2015 amid Hadid’s battle with Lyme disease, the record producer was roundly criticized for leaving his wife while she was sick.

“How can I leave a sick woman?” Foster says in the new documentary “David Foster: Off the Record.” “The fact of the matter is that was not the reason I left. It was for a different reason which I will never disclose that had nothing to do with her being sick.”

The duo were together for nine years and married for four before announcing their split in 2015.

His time spent appearing on Hadid’s show “The Real Housewives of Beverly Hills” was clearly not something he remembers fondly.

“My wife at the time wanted to do the show,” he recalls. “I didn’t want to be the guy to say no.”

Foster says that when someone recognizes him from the Bravo reality show he wants to say, “Hey, I’ve got 16 f–king Grammys, half a billion records. F–k that show!”

Foster, 70, is now happily married to 36-year-old “American Idol” alum Katharine McPhee. The pair celebrated their first wedding anniversary this week.

Despite the considerable age difference, the two seem genuinely besotted with each other — although McPhee admits that his reticence to delve into emotions can be irksome.

“There have been moments where you feel like, ‘God does he have any empathy at all?’” she confesses in the Netflix documentary. “He’s so good at disguising what he feels. He just wants everything to be ok at all times and if it’s not he’s gone.

“I said to him, ‘I need you to at least try to understand how I feel’ and he was like, ‘Well, maybe you should just leave then’ and I was like, ‘No, no, I know this is what you do so don’t play that game with me.’”

Foster acknowledges that he’s no angel and says he can probably be described as a “runner” in relationships — fleeing when problems arise. He has been married five times: to McPhee, Hadid, Linda Thompson, Rebecca Dyer and B.J. Cook.

“Anyone that calls me an a–hole for the things I’ve done, I think they’re probably right,” he concedes. “I think I have been an a–hole a lot. I’m not a cold-hearted motherf–ker either.”

The documentary, which starts streaming Wednesday, also features interviews with Barbra Streisand, Céline Dion, Josh Groban and Kristin Chenoweth.