"17 years ago we decided to jump into life together," Crawford, 49, captioned via Instagram, without disclosing when the snapshot was taken. "Happy anniversary, babe. I love you!"
In the photo, Crawford and George Clooney's BFF, 53, are jumping into a pool. The model is holding her shirtless man's hand while looking amazing in a revealing black bikini.
Crawford wed Gerber in 1998 three years after finalizing her divorce from actor Richard Gere. The couple are parents to stunning kids Presley, 15, and Kaia, 13.
"The good [marriages] are work," Crawford told Entertainment Tonight in February 2014. "The people that give up too early — it's like what they're not realizing is that if they just put in that extra work and they get to the other side of that then you have all this history together. We were just talking about how much we both cherish that."
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