updated 01/09/2012 AT 1:00 PM ET
•originally published 01/09/2012 AT 1:30 PM ET
Pink and her pro-motocross hubby Carey Hart may have tough exteriors, but the affection they share for one another brings out their softer sides.
“Happy anniversary to my beautiful wife who I love so much,” Hart, 36, Tweeted on Saturday. “Six amazing years and you haven’t killed me yet. I’ll love you forever.”
Pink, 32, doesn’t deny her mutual adoration for Hart, who is the father of her daughter Willow Sage, but she does joke that the rough times are yet to come.
“Yes :) I haven’t killed you yet ;),” she Tweeted back. “But give it time darling. It’s happening slowly haha. I love you honey cakes.”
The lovebirds wed in a 140-person ceremony on a beach at the Four Seasons Resort in Costa Rica in 2006.
“I became traditional and annoying and emotional,” Pink told PEOPLE shortly after the wedding about planning her nuptials. “It was really strange and interesting for both of us.”