The 50-year-old, who won 7 straight Tour de France crowns from 1999 to 2005 (but was later infamously stripped of the honors), initially began dating Anna back in 2008 -- and he said in his post Tuesday she's been his "absolute rock the past 14 years."!

The two have two children together -- and Lance said he was so happy both could attend their ceremony, calling it "so special."

"I love you immensely," Armstrong said to Anna in his post, "and will always be here for you and our family."