"I'm just blown away by the beauty of it all," he says. "Especially when I see anybody performing at the peak of their ability. I see it, and I f**king weep."
As ET previously reported, Hamm and Westfeldt, 47, issued a joint statement when they called it quits in September 2015, shortly after the actor's brief stint in rehab for alcohol abuse.
"With great sadness, we have decided to separate, after 18 years of love and shared history," the statement read. "We will continue to be supportive of each other in every way possible moving forward."
At the time, a source told ET that the breakup occurred a few months before the two announced the news, and that it was due in part to Hamm's "party-heavy lifestyle."
"Jon and Jennifer really fought hard to make their relationship work, Jennifer more so than Jon," the source claimed. "They were together for many years, but in the end, it was too much work. It's no secret that Jon likes to go out and leads a very party-heavy lifestyle. And Jennifer was just tired of that."
"She wanted him to grow up … and he never wanted to," the source added. "She was tired of being his mother."
In his latest interview with InStyle, he touched on what it was like going to therapy as a public figure.
"Medical attention is medical attention whether it's for your elbow or for your teeth or for your brain," he explains. "And it's important. We live in a world where to admit anything negative about yourself is seen as a weakness, when it's actually a strength."