Oh, I know how you feel. My hubby has to work nights sometimes with his job. At first, it would take Hobbs a good hour to settle down at night because he was so used to having both of us there. He would jump on and off the bed several times and sometimes even sleep in my hubby dirty clothes basket.
It has been about 2.5 months now that hubby has started working one or 2 nights a week, and Hobbs has just gotten used to it. He settles down and goes right to sleep now. It will just take Howie some time to get used to now having 2 people there, but he will eventually get used to it and settle down.