The Qatari businessman posted the note on his website.
"To the most beautiful person in the world, thank you for your divine love, your eternal support and for being my best friend. I love you so much, inshallah we will be together in the Great Forever x (sic)," Al Mana wrote along side a black- and-white photo of Jackson.
The post comes after Jackson took to her website on Saturday to share the first picture of her three-month-old son Eissa Al Mana.