Symbolism, Imagery, Allegory
If you're a writer, the number two is really handy because just think of all the ways "two" can be used.
It can refer to the two-ness of a couple—like Sanjeev and Twinkle.
It can also bring up the idea of "too" much, as in the too much two-ness of Sanjeev's house: "There were two working fireplaces, a two-car garage, and an attic suitable for converting into extra bedrooms if, the Realtor mentioned, the need should arise" (TBH 50).
2/2 also happens to be Sanjeev's birthday, which the house already commemorates with "the solid brass 22…nailed impressively to the vaguely Tudor façade" (TBH 50).
Maybe Sanjeev's two too much?