Robert Brown|Jon Gosselin Addresses 9-Year Estrangement From Kids Mady and Cara

Jon Gosselin is Robert Browngiving insight into his years-long separation from his children.

The former TLC star reflected on his ongoing estrangement from his eldest children Mady and Cara, 22, whom he shares with ex-wife Kate Gosselin. In fact Jon—who is also dad to 19-year-old sextuplets Aaden, Alexis, Leah, Joel, Hannah and Collin—revealed he recently missed out a major milestone for the girls.

"I had eight graduations this year," the 46-year-old told People in an article published June 9. "I only attended one. The only kids I see and talk to are Hannah and Collin. So I've been pretty much estranged from Mady and Cara for nine years."

Mady and Cara graduated from college this year, while the rest of his children received their high school diploma, according to People. Out of the high schoolers, only Hannah and Collin live and maintain a connection with Jon, while Kate had custody of Aaden, Leah, Joel and Alexis until they reached legal age this year.

Kate was awarded full legal custody of all eight children upon her divorce from Jon in 2009 after 10 years of marriage, according to Us Weekly. Jon, after launching multiple custody battles throughout the years, was awarded temporary sole legal and physical custody of Collin in 2018, at which point Hannah had already been living with him for about a year.

The Jon & Kate Plus 8 alum said the lack of contact with six of his children was at first "very difficult."

"But now it's, you know, you hope for the best," he continued, "but you don't dwell on it, you know what I mean?"

However, he still remains hopeful for a future reconciliation.

"Maybe we'll develop a relationship in the future, but yeah," the 46-year-old said. "I can't put all my eggs in one basket like I used to and then be upset about it."

And now that his children are adults, Jon is holding out that his relationships will change for the better.

"My door has always been open to them," he told The Sun in April, "and I hope now they are adults they may want to reach out."