Zoya, Vega or neither?

I just finished rereading Cancer Ward, and I decided to try to grapple with exactly what Oleg does at the end, when he ignores both Zoya's and Vega's invitations and goes off alone back to Kok Terek. Actually some time ago, it occurred to me that there wasn't anything really surprising about this, it is like the cliche in American culture that holiday romances never last. Both the relationship with Zoya and with Vega were hospital romances, and when outside the hospital, they suddenly made a lot less sense than before.

Although I think Oleg was more tempted by the relationship with Vega than the one with Zoya. They had a valuable friendship, more than just the sexual desire element behind the relationship with Zoya. Note well, I am not saying Zoya was merely a desirable body, but that Oleg's view of their relationship was predominately of her as a desirable body. As proof, there is the passage about the unusual tightness in his chest when he's thinking of Vega, and he thinks that the attraction to Zoya is a completely different part of the body altogether. I do think Solzhenitysn wants us to have a respect for Zoya, the description of her thinking of her future and what it ought to mean midway through the book shows her as a person of intelligence.

But besides the hospital romance no longer being compelling after leaving the hospital, Oleg is constrained in thinking of a relationship with Vega, in worrying about what the hormones have done to his sex drive. A very understandable reaction. But I'm tempted to think if I was there, that I'd ask Oleg to reconsider. In leaving, is he not making Vega's choice for her? Maybe something would be possible after all?