You don't have to be in an actual physical relationship.
I think I sleep just fine if I have some thought of a person that I can imagine. She could be the nice delectable young thing that I happened to notice whilst meandering through Chapters one evening - sitting there in a corner with her legs folded underneath like some yoga position, or else some brown-haired maiden wistfully wandering through the racks, toying with her curly locks and swinging her handbag behind her as she cranes forward, peering sideways at the binder titles, printed perpendicular to the ground. Or else a chance encounter with a person that leaves you wanting more - mentally and or physically.
Physical doesn't neccessarily mean sex. To paraphrase - sex if neccessary, but not necessarily sex. There is so much more to being physically intimate, the nuzzling, soft caresses or the semi-firm hand, feeling its way over flesh. Bone, skin, fat (yes, we're human), hair and even the smell of things - skin, hair. The scent of the small of the neck is different from that over her arms and similarily off her midriff.
To go to bed alone is a sad and increasing modern fixture. Not that the ancients were bedding each other on a regular basis. Women certainly have a greater variety of choice and the means of finding that choice. The arrival of the internet and the advent of online dating has brought an unhitherto large number of willing, fit, employed, and mildly interesting males in not only the reach, but the consideration of today's female at the touch of a button. A few clicks and phtos aside, the ability to find not just a mate for lifelong bliss, but a blissful nitelong mate is unprecendented in our history and has dramatic social and cultural consequences.
No longer are women subjected to the social graces that attend the ritual that is the stylized search for male partner, never mind a partner with whom to spend a lifetime with (or perhaps until something better, or richer, or prettier, or healthier, or fitter, or smarter, or just plain interesting comes by). Now they can do their shopping for humans online and there are plenty of men willing to advertize themselves, sometimes truly, sometimes falsely but always there is an overabundance. What to do as a woman? Take your pick. This may actually not be so simple as it sounds, for almost all women will have said this at one time or another "I don't know what I am looking for - but it's not you". And there's the problem - most women are looking for the same thing, in as much as most men are looking for the same thing. And women carry more of a social program in their head with them, enough to come up with the notion that if I am asking you out, then I must think that we are on the same level of attractiveness (or did I read that in a Dilbert comic strip?), whereas men are simply happy enough for you to have said yes, never mind the utter banalities of figuring out what to do with you once we have you on the way to a restaurant, cinema, coffee shop , whatever.
Are you selling yourself short by selling yourself electronically for all the superhighway to see?