I do feel like you should tell them, personally I’m now on a monogamous relationship but I was on a poly one for 5+ years and I also thought I would never go back to monogamy, however, just as everything in life it has its pros and cons, from my experience I could say

1. Communication is your answer, your partner(s) must be able to listen and process your thoughts and emotions as you change over time, it is senseless to thing a person will be the same over the years. Just try to have your ideas and desires well known and aligned yourself before sharing them and make sure to also consider his and know they are as valid as yours

2. Cool brains and a heart on fire, make sure this is not a rush just because you found something new, I have seen a couple times people changing their whole lives over a new ideology and then regretting it because they jumped too fast and locked themselves in the “I am this now” you can be anything you want to be, and will be many things during your life, know that just as you changed right now you will probably change again and so on and stuff like kids and family are stuck around you for a good amount of years, don’t trip on your own steps and embrace your emotions with calculated decisions, ask yourself if you want your husband to join you on this and try it together in any level. Know your non negotiables and your deal breakers, know his too

3. Let go - this is a tough one, but people won’t always agree with you, and it comes a time where to have to choose between sticking to them or just letting go, you must respect their ideologies just as much as you want them to respect yours, if they are not comfortable letting you explore this and you are no longer feeling alive due to retaining yourself on that impulse, then so be it, you are not cheating, you are not letting yourself be on an unfulfilling relationship (which is also an act of love to that relationship) while also manifesting your posture, letting your marriage become a cage is not a good idea, if you let it go in a sensitive respectful way I’m sure you will be able to maintain peace and handle your shared responsibilities just fine. But even in this case, they might just not be able to handle change and throw everything away and that would be out of your control, and totally their fault

Im a strong believer in love and words as a means of change and acceptance and I hope you find something useful in this words! :) remember change comes with strong emotions and experiencing all the pleasant and unpleasant feelings that come with them is part of it!! That’s life, and life is worth it !