I answered "No" because the question is so misleadingly asked that it is effectively gibberish.
What does "natural" mean? Human beings are capable of both monogamy and polygamy. Different societies have had a host of different kinship rules.
In societies where there is no contraception, protection from sexually transmitted diseases, and paternity tests, monogamy becomes very important to insure that no partner has to raise a child who is not theirs without their knowledge and/or consent. Monogamy also thereby reduces the possibilities for sexually transmitted diseases to spread.
In our society, it is much more natural to explore polyamory.
There is no "nature". We have a range of expressions that our genes allow, but where in that range we will fall is fixed by a host of factors, including our own choices and our individual needs.
I would say human beings are predisposed to want to have close intimate connections, and that monogamy is one of the easier ways of doing that without risking jealousy. Aside from that, I think nothing can be said reliably in the abstract.