"That" sort of relationship is one with typical primary style entanglements like shared finances, living together, the "normal" stuff which I feel is very difficult to replicate. What you can do is shun the correlation people generally apply to practical entanglements and romantic commitment. You can't make other people do that though.
Overall, I think the best thing you can do to "prove people wrong" is be happy and healthy whilst doing whatever they believe you're doing wrong. If one's friends are against polyamory and then they see one having unhealthy and unhappy polyamorous relationships, it will only serve to prove them right.