One thing that has helped us is to normalize the whole thing. LOTS of couples spend time apart for various family, work or friendship reasons. Maybe your partner isn't doing the same things while she's away, but the 'away' part is perfectly normal for a lot of families.
It's been helpful for both me and Mr. D to reach out to our friends when we're home alone (with or without the kids). I HATE being in the house alone -- I swear, it doubles in size without the family here, and suddenly I feel like I'm in a gothic mansion instead of a suburban split level. So the last time he traveled and the kids were gone I crashed a friend's boy's night at the movies, and went to the beach with some girlfriends the next day and stayed over at a friends house after drinking too much wine and eating too many brownies. None of them knew that he was on a date, but it didn't really matter. They did know that I HATED being in the house alone and were more than happy to provide distractions. Mr. D does the same thing when he's single-parenting. It doesn't matter whether I'm on a date or on a work trip, he still sets up supports for himself and makes plans to enjoy the time he has.
If your problem is the relationship it's self, I'd have to place myself firmly in the "suck it up" camp -- it's something it behooves you to learn to get over. But then, most of my relationships are long-distance and overnights are the only way we can have relationships at all. Do I occasionally take the not-quite-indicated-by-my-allergies dose of Benedryl when I'm in that big bed alone and awake thinking about how much fun he's having? You betcha. But then I work through those feelings in the morning because that's *my own* problem and not his, and I am ultimately the person who has to deal with it.