Yes, you can stay in this relationship for Z. The lesson for Z would then be taught is that relationships mean being unhappy and in a loveless partnership.

You don't seem a good fit for one another. Not to mention that there were so many red flags from the very beginning, yet you decided to still get together.

Your options are simple: stay if you both want to work on the relationship OR leave so you both get a chance at happiness.

Whether you stay or leave, one thing seems imperative and that is to work on yourself. You have been (and still are) carrying *a lot* of issues into this relationship, which may have contributed to the unhealthy status of this relationship. WOrk on yourself so that you do not bring this into any other relationship. And you may also be happier within yourself.