Boy Meets World's William Daniels, 99, Had An 'Open Marriage' — And Research Backs Him Up

Even as views on marriage and love evolve, open marriages continue to be met with skepticism. Whenever the topic comes up in conversation, people usually discuss themes of jealousy, unfulfillment, and the true meaning of commitment. There's no denying that open marriages come with their unique set of challenges. However, the flip side of those obstacles can be seen in stories of couples like William Daniels and his wife, Bonnie Bartlett, who have shown us that it is entirely possible to have a thriving relationship whilst being in an open marriage. 

Speaking to the Daily Mail in 2026, Bartlett said that she felt it was only normal for people such as herself who had been in decades-long marriages to be attracted to other people. She then stated that she and her husband never formally outlined the terms of their arrangement, adding, "We just live our lives. And if he's away for a year, he's away for a year." Bartlett stressed that they both remained committed to each other even as they explored outside their marriage, noting, "We never got unhinged, but our lives did go in different directions occasionally." 

While discussing her 7-decade-long marriage with People in 2023, Bartlett said, "I never felt tied to fidelity, and neither did Bill." The "Twins" star went on to admit that their marriage could have easily ended if either of them had fallen head over heels for someone else during their open marriage era. However, that never happened because they couldn't envision being with anybody other than each other. The fact that ethical non-monogamous marriage can actually be healthy isn't just backed by their story but also by research.

According to a 2018 study published in the Journal of Social and Personal Relationships, anywhere from 3% to 7% of North Americans were in consensual, non-monogamous relationships. The study compared the levels of happiness in people in monogamous vs. non-monogamous relationships using questions that determined how often they thought of breaking up, their level of trust in their partner, their overall happiness level, among many other things. Ultimately, the study found that people in open relationships were just as happy as those in monogamous relationships. 

Another one of the study's main findings was that the level of happiness in a relationship didn't depend on its structure but on the motivations for initiating sex. If people in either type of relationship chose intimacy out of a desire to deepen their bond with their partner or a genuine sexual need, they were far more likely to be happier. Additionally, Psychology Today notes that a 2020 study found that relational and personal satisfaction levels remained the same before and after people opened their relationships. However, sexual satisfaction did increase. 

Moreover, in a chat with PsychCentral, licensed marriage and family therapist Ashera DeRosa professed that monogamy wasn't necessarily the only path to a happy relationship. "Relationship structures are only as healthy as the participants," she explained. "If everyone involved is communicating effectively and being proactive, I see no difference in outcome when it comes to structure." Still, it's best to weigh the decision against its pros and cons because marriage can affect your health in surprising ways. In fact, even your partner can affect your health in surprising ways.