Educate yourself about what it is to be a mono in a poly relationship. While no relationship is exactly the same most monos experience many of the same diffculties. You mentioned some of them yourself (jealousy, envy etc.) and in the link below 11 Do's and Don'ts, I bring up things that most women would never dream that they would have deal with in an otherwise healthy relationship.
Re: Examine yourself. You plough through all the extraneous shit and find what is really important. For me it was having a committed, beautiful, deep and meaningful relationship that kept me growing. Z being poly doesn't exclude any of those things in reality. Let's say I was a born- again Christian who saw polyamory as fundamentally wrong (not all Christians are in this category but some are).Then polyamory would never be truly compatible.
Well by that final definition of yours I would say that I am well and truly over the line.