I don't understand why none of your doctors (especially a neurologist) GUIDED you on the road to taper and cease taking Effexor, especially to help your body prepare for conceiving and giving birth to precious life.
This is not a drug for a person to deal with by him/herself. Especially dangerous to just suddenly stop taking because it can (and has) lead to heart disturbances with even death. And it lingers, taking considerable time to eliminate, and even then it can LINGER. I KNOW FROM PERSONAL EXPERIENCE.

How did you come up with your tapering doses?

After having been on Effexor Extended Release for over a decade, I sought the help of a trusted neurologist to design a tapering schedule (with dosages), and embarked on a seriously long, difficult road that was at times excruciating, all while working full time teaching secondary and graduate school and helping an elderly mother. Dosages were tapered over time, not just days. What I experienced was pure hell at times, but I desperately wanted to get out of the grips of that horrid medication. If it was meant to help with major depressive disorder, then why was I still so miserable while taking it? And having all the hallucinations, night terrors, "fuzz brain", etc? No, that was one helluva drug and I wanted OUT. I was under medical supervision while "detoxing" (what I called it). When finally completed with the tapering schedule, I was grateful and somewhat elated but felt no escape from depression (but what the heck, even while on Effexor my emotional/mental states had not ameliorated, instead had DETERIORATED).
Several people have posted here on this site their personal tapering formulas, etc., and a few have asked me for mine. But I have NOT offered any such info because in my opinion it is highly inadvisable to give such details about medication, particularly one as dangerous as Effexor. One MUST be under medical supervision, and not battling this drug demon by oneself.
I urge you to seek professional advice and supervision during you efforts to shed this medication.
You owe it to yourself and the children that you and your partner want to have.
Prepare a self-care routine in which to engage during this journey, for you will experience challenging and demanding side effects. I hope you have a supportive team of doctors, family, and trusted friends.
I wish you the best, and my prayers will be sent your way. 💖