Relationship with one woman
Pros: companionship (this is the best imo), help with practical things aka teamwork, "love" - being a mixture of feelings of fondness and nostalgia (not sure this actually is a pro), may improve social status in ways
Cons: sex gets stale (yes it does, don't lie to yourself), fights are pretty much part of the deal even in good relationships, more expenses, no freedom to do exactly what you please at any monent, the social life suffers
No right or wrong in this one. Everyone can't be single and vice versa.