The actors, who are set to mark their ninth wedding anniversary this year, both posted to Instagram to celebrate their love.
Reynolds, 44, posted a sweet slow-motion video of his wife sledding and a photo of the pair posing together while all dressed up, with the caption: "My forever valentine for the foreseeable future."
Meanwhile, 33-year-old Lively shared a time-lapse video of him doing her hair, and like her husband she posted it along with a sweet photo of them together.
Taking her tribute in more of a risqué direction, she wrote: "That time I f*ed my hairdresser."
The pair welcomed three daughters – James, six, Inez, four, and Betty, one – after tying the knot in 2012.
Their wedding took place at Boone Hall, a South Carolina plantation with a brick building business that relied on the labour of enslaved Black people in the years before the Civil War.
They apologised for their choice of venue last year, with Reynolds explaining they had chosen it based on Pinterest photos.
"It's something we'll always be deeply and unreservedly sorry for," he told Fast Company. "It's impossible to reconcile."
"What we saw at the time was a wedding venue on Pinterest. What we saw after was a place built upon devastating tragedy."
They later held another wedding at home.
Reynolds was previously wed to Scarlett Johansson for two years before they divorced in 2011.
Watch: Blake Lively felt 'alienated' not being able to fit in designer clothes after giving birth