I read your message about an hour after you wrote it. I started then praying about how to respond to you... and if it should be me responding to you. Went to church, ran a few errands, had lunch, you know... the typical things. I really prayed that God would send someone else to respond to you because I didn't want to do it. Alas, you do need a response and as you are still on my heart, I'm in. Here goes.
Debra, you have stepped outside of your vows. You promised to stand by your husband in sickness and in health. I believe that alcoholism is an illness, and an addiction.
I agree that it was probably healthy for you to separate from him for a time, but honestly, I think it's terrifically ill advised for you to have a boyfriend. If you are at all intimate with this boyfriend, you are in adultery - and to be honest, a married but even a separated married person dating someone who is not their spouse is committing adultery - in the strictest sense.
I don't know what reference you are talking about with regards to dissolution, but someone who hid alcoholism from you may have been a valid reason in the beginning for a dissolution based on fraud, but I doubt that would be the case 25 years later. You say above that your husband has been abusive, and that is VERY disconcerting. Have the two of you sought counseling together?
You mention in another thread that the current boyfriend is an atheist and you are returning to your Christian beliefs. I would caution as the Apostle Paul does about not being un-equally yolked. Being romantically involved with a non-believer is rather unwise. IF God brought you into his life as a witness, it would NOT have been as your boyfriend, because God doesn't bring us into sin to spread the Gospel.
Regarding grace. Yes, there is an abundance and I am so thankful that God is so gracious. we have to be very careful about not walking in sin if we know the truth though. I don't think that God banishes us forever for sinning after we've experienced salvation, that would be like banishing a baby or toddler for falling down as they learn to walk and run. He loves us better than any parent. Keep in mind though that there are natural consequences to sin. And even still, God is a God of restoration and he wants to restore us to himself.
So, what do you do? My advice is hard, and I am so sorry that it is, but... I think you need to end the relationship with the boyfriend (though I see that you posted that you are currently separated from him while considering God's plan for you. I am sure it's difficult and confusing, but I applaud you for that).
If your husband had not been violent, I would suggest attempting to reconcile with him. I don't know if there is any counseling the two of you could do together. God does honor the marriage vow and he does intervene and cause change in marriages. Is your husband a believer, a practicing Christian who has fallen into habitual sin? I don't know.
It's on that point I would focus my prayer energies, on God restoring your marriage better than it was before and healing your husband (which won't be an easy road). Your conviction in honoring your vows before God and to him may bring him back into covenant relationship with God too.
It's very complicated, and this is my advice with this very little bit of information: Pray and seek God. He does give answers. Don't make moves based on your feelings (I'm so in love with BF) but based on what you know God would want you to do (and again, stepping outside of your marriage is NOT what God would want you to do).
Praying for you Debra. My in-box is open if you would like to talk further.