Any suggest on advise about a divorce?

I have been seperated for appr. 4-yrs. My husband left me for another girl. I have been trying to date but have been hoping to get back with my ex. He has lead me all this time but has not taking any steps to get rid of the other women. I am done with all of this, but have the dilemma of now having to get a divorce. Every Lawyer I have talked to wants at least a 2500 dollar retaining fee. My son is going to college and I am still raising my 8-yr granddaughter that he agree to help me with 8 yrs ago. I also own a home with him, that I do not want to loose. I have been living in the house and paying close to 2000 a month. He has been giving me 700.00 a month when he wants to. Does any one else out there have any other solutions on trying to get help on getting a divorce, that does not cost so much. I live in Wahington state. And men I am not trying to take him for all his money It is just time he pays his amount. He makes three times more then me but never has any money