I'm not entirely clear.
Are you are crushing from afar and the woman doesn't even know and you just suspect she crushes back?
Or actually TOLD the woman of your crush and it's now an emotional affair because she CONFIRMED she crushes too and you are all loveydovey with each other?
Either way -- just get it over with and come clean with your husband. You did a lie of omission not telling at the start about your bisexuality and now you are compounding it with the pseudo GF.
He has the right to know.
Apologize for the lie of omission, ask for forgiveness and opportunity to make ammends.
If your emotional intimacy with your spouse is tight AND you have tight friendships, that's one thing. But it is not fair to practice emotional intimacy with other people while you deny your own husband the same opportunity to be emotionally closer to you. What is he? Chopped liver?
We have too much history, responsibility, and love. I really regret not being honest with him at the beginning.
If this is the case, then take steps to get back into right relationship with him NOW. No time like the present.