Should I stay in an unhappy marriage?

My husband and I have been married for 18 years. We have nothing in common. He hasn't been attentive to me and the kids for years. He is a work-a-holic and has been addicted to the computer.He is also very cheap with money which has kept us from enjoying life's little pleasures. Our life is boring and uneventful!! I have wanted to leave him for quite sometime, but feel like I owe it to the kids to stay. ( needless drama?) also, Im attractive, but almost 40, and Im afraid i may not ever find anyone else, with my age, and having 3 kids. Im afraid the gr wouldnt be greener on the other side. I do work, but I dont make enough money to support my kids and find a home, etc.I dont want my kids to go without. I feel stuck in a very sad, lonely marriage. Not sure where to go from here. Advice? (Oh, and weve tried counseling. Hubby didnt want to pay for it anymore, because he felt as if it wasnt "worth it." Plus, he lied to the counselor anyway. )