E.S.
When I got divorced, my daughter was 3 years old, but I had been separated from her dad for over a year. We were able to maintain a very amicable relationship, slow distancing versus an abrupt change, so she's done quite well. I made the mistake, however, of spending extra time with him before his deployment to Iraq in January. Now, my daughter thinks that when he returns, we will all get together again. Wrong.
For me, there is "someone else." This guy is someone that I would have jumped in the sack with very quickly, but he's older and he's made me wait - how rude! :) Seriously, though, I realize, after much frustration, that he has been right to do so.
I'm a decade older than you, but I know, believe me, a year seems like a really long time when you're 25. At 36, it still seems like "quite a while."
Since it doesn't seem you've gone through a divorce, I'm guessing you weren't required to take the Child Education class that's required for couples who are divorcing that have children. I was SHOCKED to learn that it's 3-5 years before anyone - parents or children - should have a new someone significant in their life. I'm getting a degree in counseling and I'm still shocked at how long a period is recommended.
The absolute best thing you can do for you, and your boys, is learn how to be by yourself. Whether you go to counseling, read self-help books, spend a lot of time in prayer, go online to chat with other women, whatever you have to do, find a way to be happy by yourself. That way, when the right man comes along, he'll be an addition to your already full and happy life - not what completes your life.
Your boys have to learn from you what it means to be content and self-sufficient. These are hard things to swallow, and I feel for you - a lot of lonely nights behind and ahead of me -but I know that when I'm 45, I'll be much happier about myself and my life if I can say that I didn't put my daughter through one bad relationship after another. Trying to save someone else is simply not as important as trying to protect your kids.
When you end this relationship with a mentally ill man, and don't kid yourself, he is mentally ill, your children will feel rejected and hurt. And again, it will take a lot of time for them to adjust, but they can and so can you. And the stronger you are, the better they will adjust. And when they ask, "Where's Jack?" Tell them - "We won't be seeing Jack anymore. I know that makes you sad, and it makes me sad, too, but after a while, I think that we will all be a better family together without him."