Welcome to our forum.
You'll have to make your own decisions as to how to conduct your own life, and communicate those to your husband as best you can. Is this a road to divorce? I don't know. You can explain to him that he can seek out additional partners as well, but not all spouses are interested in that. Some just want to stick with the one person they married.
If that be the case, you could tell him you've decided to live polyamorously, and he can support your decision or not support it. Some mono/poly relationships do succeed, but your situation is your own.
I hope Polyamory.com is helpful in giving you ideas of how to navigate the uncertain waters you're sailing in. Let us know of your thoughts, questions, or concerns.
I agree that you just have to be yourself in the end.
Love means never having to say, "Put down that meat cleaver!"