The resurrection of the ex-wife aka Satan

My husband and I are expecting our first baby together this fall. We have been together 5 years and married for over 1. Lately, his ex-wife is causing a lot of stress for us and I am getting fed up with it! Don't get me wrong, I'm in it for the long haul with my man (and his boys) but juggling this with my pregnancy is really exhausting me. I got mad at him today and asked him to stand up and fight for our family. All she wants Is more and more money hand over first on top of the already VERY high child support she gets weekly for his two teenage boys he has with her. We take care of them when we see them at our respective times, split cost of braces (for both), pay extra money to let them play in soccer leagues etc. My husband is the best dad he can be and then some! I get so angry bc of her history of emotional abuse with him and the fact that she's turned it up a notch and is constantly butting in demanding more money and threatening court. (I think she is resentful that she is now on her third marriage and he is happily married and in a healthy relationship)
I guess my question is, do you guys think it's worth just dishing the money on a lawyer to stand up for ourselves and go to court to draw some hard lines in the sand with her or just take the money we would spend on court and give her what she wants? 
I'm a firm believer in standing up for yourself and our family. He just wants to do whatever gets her off our back fastest which makes me upset because he's just giving in to everything she wants and leaves little to nothing left for our family!!!