The 36-year-old country music star and former "American Idol" winner had nothing but praise for Fisher in an Instagram post Tuesday following the 11th anniversary of when they first met.
Underwood and Fisher celebrated the occasion with a "rare night out" at Del Posto restaurant in New York.
Underwood shared a photo from the outing and toasted to her future with Fisher in the caption.
"11 years ago yesterday, I met the love of my life... patient, kind, the best dad, handsome, of course!," the star wrote.
"Someone who accepts me and all my flaws... the same as me in many ways... opposite in some. But he is my match. The iron to sharpen me."
"Tonight we celebrated at @delposto. A rare night out with amazing food and even more amazing company and conversation. Here's to so many more years together. Love you, babe!" she added.
Fisher responded with a loving message in the comments.
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"Love you babe you're the best," he wrote alongside a heart-eyes emoji.
Underwood and Fisher married in July 2010 and are parents to two sons, 4-year-old Isaiah and 8-month-old Jacob.
The couple welcomed Jacob in January after Underwood experienced three miscarriages in two years.
"Of course you wonder if it's you, what am I doing wrong, or what I have done wrong. I remember having conversations with Mike trying to make sense of it all," Underwood said in the July 1 issue of People.
"I don't want to complain, ever," she added.
"But the miscarriages made me get real with God and say, 'Okay, I'm kind of giving up a little bit. If this isn't meant to happen, then I need to accept that and know that someday I'll understand why.'"
Underwood released her sixth studio album, Cry Pretty, in September 2018.
She will host the 2019 CMA Awards without longtime co-host Brad Paisley in November.
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