Should I let my wife go.....or get her to stay? Help?

Last night we had a nasty arguement, and she left, only to come back and sleep on the couch because she had nowhere to go. We've been together for almost five years and gone through hell with her family due to a custody issue with her son. The biggest problem between us is that when we find time together, we end up fighting and argueing when we should be getting along. She's stressed out because of her family and her son. She now has almost no contact with any of them. She's also jobless at the moment, and has a hard time finding a decent job. She's emotionally abusive to me and my kids, but doesn't mean to be. She has a strong heart and I believes she loves me dearly, but I can only take so much. I'm losing optimism for the future with her. I find it harder to envision doing the things I want to do with her, having financial security with her, and my kids growing up well adjusted around her. I've looked into therapy for her, but is it too little, too late? Advise me please.