I know this is a long post, but I really hope the OP, as well as others, give it a read. I feel it contains very important information that I gained from mine own personal experiences. The TL;DR is that having an addict father FUCKED ME UP. Here goes:
I cannot even begin to describe, in words, the impact having an addicted (alcoholic) father had on me. It might in fact be impossible to describe every single obvious and far reaching effect this had on my life, all of which were negative, to clear up any question of whether or not it was a "good thing". It was far from a good thing. Sure, he was PHYSICALLY AROUND, but I effectively grew up for 15 years without a father: I never had him "there" to show me "how to be a man," I never learned how to flirt or ask out a girl, I never had a father who wanted to have catch with me (unless he was sober), I never had a father show me how to have a healthy relationship with his family, or his children, UNTIL HE GOT CLEAN!
He did get clean, when I was around age 15. And he has done his best since then, but even his best intentions now neither atone for what happened to me, nor repair the damage. It was impossible to fix: the damage was done, end of story. And after? having a father for the past 6 years? It has not undone lacking one for the first 15. I became a heroin addict myself, in part because I consciously choose to steer clear of alcohol, although ironically fell into other drugs due to my logical thinking and obvious genetic abnormalities. I justified other drugs but shunned alcohol because I saw what it did. Your children might do the same: they may shun heroin, dump on drugs, etc, but think it PERFECTLY ACCEPTABLE to drink their problems away! In fact if they do suffer the way i have, i'd put 1,000$ on alcohol being their DOC.
Am I saying this is guaranteed to happen? Absolutely not. What I am saying is that it is a very, very, very distinct possibility, which you should be aware of. Do you want your children becoming addicted to another substance? They definitely will avoid heroin like the plague, but they'll justify other cheap escapes (ie drugs), in particular a legal one. I shunned the legal one but ironically thought (at the time) that the illegal one was more acceptable. "Oh, well opiates make me BETTER! They make me more social/more focused/more studious/etc, and whats wrong with a release like that? My parents utilized drugs in some form, why cant I use a different one!"
Your children becoming addicts is but a single, solitary, personal example of the possible damage done to them. I have not even delved into the complex underlying emotional issues that I experience (should I love a dying man who was never there for me, but is trying to make up for it now? Do I forgive such a man for doing this to me? How do I BEGIN to do so? Why SHOULD I do so?) such as: never completing projects because they never received constant encouragement, never being able to deal with a family in the correct way because they had nothing but bad examples, always acting out because they seek attention from a parent that does not give enough, etc etc etc. There are a million ways that your children could be negatively impacted. Some of which could quite possibly be unique to your situation, and not previously heard of, meaning there might be no way to "fix" the damage, if there even is a way to fix ANY of this damage.
In short: your kids are going to be fucked up. Sorry to put it so bluntly, so harshly, and frighten you so. But man, if I could save other children from suffering in the same way I did...then hurting your feelings and scaring you is not only of no consequence, but I would do it a hundred times over.
Just be aware of the damage you are going to do to your kids if you don't get clean. Please be aware that your actions are going to have true, deep, consequences and inexorably change the lives of your children. I would not wish my worst enemy to lack a father, any more than I would wish them to have a heroin addiction.
Once again, no guarantees either way. I am not definitively saying your kids will be fucked up, or wont' be. I am just saying you are stacking the odds so against them and not giving them a fair shot at a happy, normal lives themselves. I am assuming based on what you've written, that you obviously hate being an addict: why would you want to put that same onus on your kids? Why would you want to put ANY unnecessary burdens on your children?
Do them the favor: get clean, or allow them to have another father. Children need a father, I wish I had one during my own childhood.