“There were hundreds of films made about Generation X in the 1990s,” says Ed Burns. He should know: As the writer and director of “The Brothers McMullen,” “She’s the One” and “No Looking Back,” he was the one who made them. After 30 years and a lot of growing up, he draws on that source for his 14th film, “Millers in Marriage,” the story of three siblings navigating life and love – no longer as angst-ridden, untested twenty-somethings, but as adults now on the verge of middle age.

“The coming-of-age stories we wrote in our twenties and thirties were these character-driven looks at relationships and careers,” Burns tells Variety. “But now I’m in my mid-fifties, and I’ve looked at that time as another coming-of-age moment.”

In the film, which premieres at the Toronto International Film Festival, Burns plays an artist who begins a romance with a former colleague (Minnie Driver) of his ex-wife (Morena Baccarin); Juliana Margulies plays one of his sisters, an author whose success has eclipsed that of her husband (Campbell Scott); and Gretchen Mol plays the other, a former singer-songwriter struggling with her domineering, alcoholic partner (Patrick Wilson).

Burns stresses that he rarely draws too much inspiration from his own experiences, but as much as he was drawn to exploring the larger, existential challenges of adulthood with a capital A, he admits that some of the dilemmas his characters faced hit closer to home than others. “I was excited that there wasn’t a movie about us that referenced the ‘tininess’ of real life,” he recalls. “Do you have anything else to say? Will anyone care? Am I still relevant? Is it time to start over or are you just riding it out?”

For a filmmaker who had to beg, borrow and steal to get his films made, one question was more important than all others: “Is there anyone out there who cares enough about the project to finance the film?” Burns, who reteamed with his longtime producing partner Aaron Lubin for the film, said he designed “Millers” based on the same model that has brought them success since his 2001 film “Sidewalks of New York.”

“Our goal was to make these modestly budgeted character-based films and try to make one every two to three years,” says Burns. “I’m coming up on the 30th anniversary of ‘Brothers McMullen’ and I can still do this. I’m showing this film with all these great actors in a huge venue at the Toronto Film Festival, so by our standards of success we’re absolutely insane.”

Burns also attributes this success to his professional ingenuity (“I don’t have two films that were either financed or distributed the same way”), but also to his creative rigor. When he occasionally felt in the past that he wasn’t doing his best work, Burns returned to the principles that had made his earlier films successful. “When I got there in the early 2000s, I just let the story take me on the journey – and quite frankly, there’s a certain discipline that’s lacking in these films,” he admits. “So around 2010, I thought, ‘I need to go back to school.'”

He has also installed a safety barrier over Lubin. “I think I do it instinctively now,” he says, “but I’m lucky. Aaron is a strict disciplinarian for me and asks the difficult questions. That has been enormously helpful.”

While the characters in Millers in Marriage represent a spiritual continuation of the stories Burns told early in his career, he hints that his next project will take that approach more literally. “I just finished the script for a sequel to ‘The Brothers McMullen,'” he reveals. But rather than allowing him to relive past glory, Burns says his past – full of successes and failures – has allowed him to look forward more confidently than ever.

“I think I’ve gotten better as a writer and filmmaker – which I think just comes with experience.”