@mamamia84,
What you are experiencing is the "empty nest" syndrome. And men get it worse than women do! VERY common!
Kids gone; dog dead; you look over at him - and he looks over at you - and both think "Is this all there is?" No wonder there are so many divorces after the kids leave!
It would be fun to try and seduce him again - change your hair color, gain or lose weight, dress differently, change the bedrooms around. Put him on Viagra. The point is: reinvent the marriage.
Good luck!