I can feel for your frustration. Both of my boys are completely different around my husband and I.
I think your son just loves you to pieces. The whining and throwing himself on you, I think, is his response to someone he knows loves him with everything she has! He knows you will take care of him, make him feel better when he's hurting, and he knows that you won't judge his whining behavior--you just let him be himself and he is very comfortable with you.
This does not make it any easier to be the joy of any child's affection. I could just go crazy some days with all of the attention my boys want from me vs their dad (and he's a great dad!). I really think he doesn't play with you the same way he plays with others is because he has a very special bond with you--one that will last a long time.
Good luck with your frustration. That's what this mamasource is for!
The days and years do go quickly, so enjoy every minute, even the frustrating ones!!