If you want to get out of the marriage, you are going to do it regardless of what anyone tells you. The vast majority of posters here are telling you to kick the lazy bum to the curb. A few have suggested that a marriage vow is a unique and sacred commitment to be taken very seriously. Most have stories from their own experiences or have shared the experiences of someone they know. Heck, even Tom and Kat have been mentioned.
If you came here to get support for your decision, you got it. It appears you have grown weary of the man and your marriage. You are tired of supporting the entire family. Sorry it's worked out like that for you.
I'm kind of old. I'm a man. And I've had some ups and downs in my 30 years of marriage. Here is my two cents, and then I'm done. You say he's a good man. That alone says to me that you haven't lost all hope. You have children. My parents divorced when I was 17 and I still resent some of the selfishness that caused it on BOTH sides. You have two children. Don't underestimate the emotional toll on them. Don't buy the quality over quantity argument. It sounds good but it's really just words. I look at a marriage as the most sacred of commitments because we change over the years (think mid-life crisis and menopause). If we view it like a job and I'm working harder than my spouse, then it's easy to get a new job. If we view it as a means to happiness, we will be disappointed, because I truly believe that happiness is fleeting and love is an action. If you determine to love your husband not because of who he is but in spite of who he is, you can save this. Easy...no way.
This may be the best post that I have ever read on this or any other forum.