The full caption on the Instagram of him knocking her a little kiss on the cheek reads:
Happy BAE-DAY, baby!! I can't put into words what you mean to me... You are the GREATEST Mommy and Wife a man could ever ask for. I love you to the MOON AND BACK!!! --Your Huz
What a sweet couple. They also have a child together, which explains why he calls her the "GREATEST Mommy" in his caption—it might seem a tad worrisome without that context.