Melinda French Gates said she was upset with Bill Gates’s past meetings with convicted sex offender Jeffrey Epstein, addressed the Microsoft Corp. co-founder’s earlier affair and said she and her former husband have a working relationship focused on philanthropy.

Ms. French Gates, speaking in her first televised interview since the billionaires’ divorce last year, cited many matters that led to their split. But she made it clear to Mr. Gates that she didn’t like that he had held meetings with Epstein, she said in the CBS program...

Melinda French Gates said she was upset with Bill Gates’s past meetings with convicted sex offender Jeffrey Epstein, addressed the Microsoft Corp. co-founder’s earlier affair and said she and her former husband have a working relationship focused on philanthropy.

Ms. French Gates, speaking in her first televised interview since the billionaires’ divorce last year, cited many matters that led to their split. But she made it clear to Mr. Gates that she didn’t like that he had held meetings with Epstein, she said in the CBS program that aired Thursday.

She said she herself had met once with Epstein, who died in jail in August 2019 awaiting trial on federal sex-trafficking charges.

“I wanted to see who this man was, and I regretted it from the second I stepped in the door,” Ms. French Gates said in the interview. “I had nightmares about it afterwards,” she said, adding of Epstein’s abuse victims, “my heart breaks for these young women.”

Ms. French Gates and Mr. Gates disclosed their divorce in May 2021, with the former saying in documents that their marriage was “irretrievably broken.” Ms. French Gates was concerned by her then-husband’s meetings with Epstein, with her worries dating as far back as 2013, The Wall Street Journal previously reported. She and her divorce lawyers held a number of calls in October 2019, when media reports emerged that Mr. Gates had met with Epstein on numerous occasions, the Journal reported.

Ms. French Gates said any further questions about Mr. Gates’s relationship with Epstein are for Mr. Gates to answer.

“Meeting with Epstein was a mistake that I regret deeply. It was a substantial error in judgment,” Mr. Gates said in a statement from his spokeswoman Thursday. He said he remains dedicated to his work at the Gates Foundation in partnership with Ms. French Gates.

During the CBS interview, Ms. French Gates acknowledged her hurt, anger and pain during and since the divorce. She also addressed an affair Mr. Gates had in 2000, saying she believes in forgiveness. Asked whether Mr. Gates had multiple affairs, she said he would need to answer those questions.

“It wasn’t one moment or one specific thing that happened,” Ms. French Gates said. “There just came a point in time where there was enough there that I realized it just wasn’t healthy and I couldn’t trust what we had.”

Mr. Gates said in a statement Thursday, “I will always be sorry for the pain that I caused Melinda and our family. I admire Melinda and everything she does to improve the lives of women and girls around the world, and I’m grateful for the work we continue to do together at our foundation.”

A 2019 letter from a Microsoft employee about her past affair with Mr. Gates led some board members to investigate the matter, the Journal has reported. Mr. Gates resigned from the board amid that probe. A spokeswoman for Mr. Gates has said that he had an affair almost 20 years ago and that his decision to leave the Microsoft board in 2020 wasn’t related to the matter.

Ms. French Gates also said the two still have a working relationship and remain co-chairs of the Bill & Melinda Gates Foundation, one of the world’s largest philanthropies with an endowment of more than $50 billion. The Gates Foundation recently named new board members, adding outsiders for the first time as part of efforts to boost the organization’s governance and independence.

“I believe in that institution. I believe in what we do. My values are baked into that institution,” Ms. French Gates said in the interview. She said that she would sometimes be in tears in the run-up to online Foundation meetings but that rose to the occasion, adding that she and Mr. Gates can continue to do that.

The foundation said in July that if either of the co-chairs decides after two years that they can no longer lead the foundation together, Ms. French Gates would resign as co-chair and trustee, according to terms of a private agreement in their divorce. Should that happen, she would receive funds from Mr. Gates for her own philanthropic work that are separate from the foundation’s endowment.

“We certainly have a working relationship,” Ms. French Gates told CBS. “I would say we’re friendly at this point.”

Ms. French Gates issued a new philanthropic pledge late last year, recommitting to giving away the bulk of her wealth but without specifying that it would go solely to the Gates Foundation. In that letter she also cited her own firm, Pivotal Ventures, which focuses on issues affecting women and families.

“I do believe that if you are lucky enough to be a billionaire, believe me, you can give away half of it and not change your life,” she told CBS.

Write to Emily Glazer at emily.glazer@wsj.com