Wondering what phrases English has similar to this Chinese idiom.
ABC Dictionary (GoogleBooks):
(lit) [If we/they/you were] not rivals/enemies, there would be no encounter. (fig) Enemies and lovers are pre-destined to meet; opponents always meet.
(lit. "enemy" or "rival" or "opponent") is also a term of endarment commonly used by women to refer to their husbands or sometimes children
What play(s)-on the above are there in English?