When I read these threads - I want to scream - shake the OP (virtually through my monitor) and generally jump up and down until the OP listens.
These situations (gay/HIV/BI/Emotional Affair/substitute whatever you like), never ever fail to destroy lives.
I speak from experience.
Give your marriage a last chance - totally free of the excitement of this affair. If it doesn't work, end things with your husband of 19 years in with compassion and decency. He is the father of your children - in the absence of battery/abuse, he deserves this, at the very least.
If, once you are free to pursue another relationship, pursue this man. Just bear in mind that it will affect your children.
I always feels so worried for people in situations like this, that they are so caught up in the moment that what is truly important becomes obscured. I nearly lost my family, my security, my life.
I can, without a shadow of a doubt say, that it was NOT worth it. Luckily, I managed to kick myself up the arse before I lost it all. Looking back I cringe. How could I even have contemplated losing my precious DH and the relationship I have with my kids for that?
It makes me feel ill.
Please, FH, think carefully. I'd hate to see you posting in 6 months time about how much you regret your actions and how many lives your actions had destroyed.