Dr. Romance on a partner's sleeping problems.

Dear Dr. Romance:
 I am 39 & my boyfriend is 51.  He takes Viagra & Cialis (on an as needed basis). We have a terrific relationship.  We seem to have no problem lying there & falling asleep for a short time after making love.  I have a really comfortable bed, which he acknowledges. But as soon as we try to go to sleep for the night, he is awake…all night.  I am a light sleeper, so if he is a wake I am awake.  At first, we thought it might be the medication, but on the nights he leaves, he sleeps fine at his house.  So, we eliminated that.  We thought that it would get better over time (and still hope for that).  This has been going on for two months now.  At this point, we have tried everything we know of.  Both of us are very frustrated &  he wants to be able to stay with me and sleep through the night.  Why can't he sleep when he is at my house?  What will help?  Will it get better? 
 
Dear Reader:
 
Thanks for commenting on the Dr. Romance blog. There are a lot of side effects associated with Viagra and Cialis, and they differ from person to person, so this still could be one of them. Maybe he needs to get up and walk around for a while after sex, to work off the effects.  He'd automatically do that, going home.  He should try that.  Or, it just takes longer for him to get used to sleeping with someone than it did for you.  Do you ever stay at his house, and can he sleep in his own bed with you in it? 
 
It's also possible that he's just happier sleeping alone, waking up in his own bed, and he doesn't want to tell you.