A lot of the great philosophers of the past were single men. It would be superficial to suggest that this explains all their 'so-called problems', but it might be a relevant fact to bear in mind. Chesterton says that the main problem for philosophers is to find a way to be at once at home in and yet astonished by the world. This is not exactly how most philosophers have expressed their concerns, and it is certainly not the only concern of philosophers, but I think it's not bad as an expression of one kind of problem. Chesterton's solution is orthodox Christianity. But another might be children--nothing is more domestic or astonishing than (one's own) children. And perhaps anyone you love can fill this role. So family and friends are important--this is banal, of course, but also likely to be overlooked or denied by someone who thinks this cannot be even part of the answer to the question of the meaning of life.
And another answer might be art. Salman Rushdie said he tried to fill the God-shaped hole in his life with literature. I can think of at least three ways that this might work. One is to revere the work of literature (or other kind of art) as a kind of icon or fetish. This seems to be roughly what Roquentin does in Sartre's Nausea, seeing art as having a value quite distinct from the rest of life or the world. The artist is then a kind of shaman or god.
Another way to fill the hole with literature would be if it presented you with a variety of characters, each with their own point of view and personality. These could possibly fill a friend-shaped hole in one's life. (I'm thinking of Jim Morrison singing "Music is your only friend," but I'm sure there could be literary as well as musical versions of this.) They might also, or instead, help one see more in one's friends and acquaintances, making them more familiar and/or surprising. If someone came to seem just like a character you had read about, for instance, this might make them both more familiar (so that you felt more at home with them) and more interesting than they had previously seemed. More generally, people might come to seem more interesting and worth getting to know if you take an interest in the people in books. In this case the artist is just a guide, helping you see the world (and people in particular) in a better way.
The third way is by experiencing an aspect shift. I think somewhere (a memoir by Rush Rhees perhaps) there is a story of Wittgenstein seeing newsreel of a bombing raid and saying that with different music being played the raid could seem tragic instead of, say, evil. There seem to be multiple ways this kind of aspect-shift could occur. Christians in pain might regard themselves as closer to Christ, which could make pain easier to bear (if nothing else). Readers of Philip Larkin might take a kind of pleasure in eating an awful pie in Sheffield, which could make the pie easier to bear. Perhaps this is a matter of making connections rather than seeing something under a different aspect, but in each case the connection sheds a different light on the experience. It very often seems possible to see things in a different light, which in itself is good news. When Wittgenstein wrote in his notebooks that "The work of art is the object seen sub specie aeternitatis; and the good life is the world seen sub specie aeternitatis. This is the connection between art and ethics" (p. 83e) he was paraphrasing Schopenhauer, who thought that still life paintings showed that everything is beautiful when looked at the right way. (I think the work of the Boyle family might be used as another example to make the same point.) Attentively might be the right word for what this right way is. Or lovingly. This is similar to the second case, but it isn't particularly about people and it's more about perspective or framing, and the possibility that art reveals of different perspectives, as well as the actual perspectives that it provides. In this case the artist is a kind of therapist.
(What is missing is the way that art expresses what we already feel better than we can manage. That seems like a very important function to me, but it doesn't fill a hole exactly. If anything, it makes a hole, letting out what was stuck inside, unable to be expressed.)
The title of this post comes from the song by the Smiths that talks about songs saving your life (like a life preserver, the rubber ring of the song's title). But what I'm really thinking of is two songs by Belle & Sebastian: Judy and the Dream of Horses (a celebration of the pleasure of dreams and songs, even for someone whose life has "gone wrong") and Lazy Line Painter Jane (a seemingly sad song about a girl whose life is a mess that turns into a celebration of her life, mostly by having a celebratory instrumental section at the end (around 4:23, although the triumphant horns around 4:52 clinch it for me)--odd that this should work, but I think it does).