"He was married and had a couple of kids."
This is where the story should have ended. But, you kept it going. You wrote:
My point is that I should’ve done something about this a LONG time ago. I should’ve made the move. I should’ve told him I was truly in love with him.
No, you should not have. You are incredibly selfish to not even consider the kids, much less his wife who probably worked her butt off creating a family. Marriage is hard work. I'm sure she put up with a lot of his failings at great personal distress at times. (all married people do) Who knows what kind of trauma she experienced because of the fantasy you helped promote in his mind?
You did this to yourself....trapped by your own sin.
You have been in a destructive cult your whole life and have likely been "compartmentalizing" lots of other stuff too, like WT false prophecies, CSA deception, UN deception, Malawi / Mexico fiasco.... the list is much longer.
If you still believe in Jesus, he once said that even if you look at another with lust in your heart that you are guilty of adultery. Hebrews 9: 27 says that judgement awaits us after we die. You need to repent and start acting on what you already know to be right, not only with this fantasy, but with your soul as well.
Find a real bible-believing church where you won't be viewed as a two headed Martian if you decide to accept the the new covenant "for the forgiveness of sins" (Mt. 26: 27-28)
Once you are adopted in God's family, he is likely to give you peace about a great many things. You seem pretty stuck in the past. God has a plan for you if you'll trust him.
For I know the thoughts that I think toward you, says the Lord, thoughts of peace and not of evil, to give you a future and a hope. - Jer. 29: 11