A division bench of Apex Court held as follows, (with respect to ‘desertion’)

Thus the quality of permanence is one of the essential elements which differentiates desertion from wilful separation. If a spouse abandons the other spouse in a state of temporary passion, for example, anger or disgust, without intending permanently to cease cohabitation, it will not amount to desertion. For the offence of desertion, so far as the deserting spouse is concerned, two essential conditions must be there, namely, (1) the factum of separation, and (2) the intention to bring cohabitation permanently to an end (animus deserendi). Similarly two elements are essential so far as the deserted spouse is concerned : (1) the absence of consent, and (2) absence of conduct giving reasonable cause to the spouse leaving the matrimonial home to form the necessary intention aforesaid.

Citations: [1957 AIR 176], [1956 SCR 838]

Other Sources:

https://indiankanoon.org/doc/1131783/

Index of Divorce judgments is here.