What does it mean to be in love for a long time?

This sentence comes from Qin Guan's "Que Qiao Xian". It means that as long as they really love each other, the Cowherd and the Weaver Girl can only meet once a year, far better than the average couple. Why do they have to get along day and night?

I think this sign of love should mean that it will relax you, as long as you really love each other.