Can I file for child support even though I am still married ?

I have been married for almost 9 years. My husband has been cheating on me spending thousands of dollars on other women ( I have proof) and refuses to give me any type of financial support. All the bills are behind and I cant properly take care of my son without any help. He has a full time job making about 36,000 a year. I am a homemaker and do not work. I have tried taking part time jobs but can not afford a babysitter we have a 9 year old son.