The couple, both 91, said their "I dos" in front of immediate family July 25 in Lakeside ... after more than a decade of dating. The nuptials were also live streamed on Facebook so loved ones all over could watch.

Ivan and Gerry met in first grade and grew to be friends during high school. They both went on to get married to other people, but continued to bump into each other over the years at various local events, and committee meetings to plan their class reunions.

As fate would have it ... they were both mourning the loss of their spouses -- Marian and Bob -- 13 years ago when they ran into each other at a breakfast diner.

We're told Ivan was there with his hiking group -- the "Over the Hill" gang -- and went over to say hello to Gerry. Later in the day, Gerry mentioned to her son ... if someone as nice as Ivan were to ask her out, she'd say yes.

Sure enough, that ol' son-of-a-gun Ivan did exactly that later that evening ... when he asked her to be his date to a banquet because it "wouldn't be any fun to go alone."

They've been together ever since, love to travel and have been all around the world. We're told Ivan actually asked Gerry to marry him early on in their dating years, but she wasn't ready after losing Bob. However, when he recently popped the question again ... she said yes.

All of that's interesting enough, but then there's this -- Ivan and Gerry signed a prenup! We're told Ivan wanted it to be short and simple, but it ended up being 30 pages ... much to his dismay.

The couple won't be going on a honeymoon right now due to the pandemic, but say when they do ... it'll include attending a University of Montana football game.