Interesting title. But not much detail to understand the reason for the end of relationship nor the job. If what got you into a PIP was opening your mouth then what was the reason for doing so? You did not like the wording or language used in the evaluation?

An example for me was, a new night manager comes in and gives a big speech about how it is unacceptable to not come in to work even in the case of a snow storm. Well, the next snow storm, the manager did not come in to work. So, I spoke up in the break room. I said that the manager made a big deal about not coming into work due to a snow storm. And that he himself did not come in. Well, the next day, I get called in and yelled at for saying this. I knew there was no winning. No matter what I would have said. It would not stop his revenge. So, I quit after a couple of weeks. I could have escalated to the higher up and taken my chances. But, managers tend to protect other managers. I learned my lesson. Talk less and live to fight another day.

If you spoke your mind and got shut down by your ex then probably the relationship needed some work? I did that once and I got to spend the night without sleep and apologizing for what I said. Admitting you are wrong even if you believe you are not. Well, life goes on. Hope you find other work and a better relationship. Just learn from any mistakes.