How to get rid of his ex?

OK, so I have been with my man for two years and we are getting married soon. His ex who cheated and left him. Has always called sometimes about money sometimes about wanting him back. She has started contacting me and being a bitch, I am nice because I don't want to hear it from if after. Anyhow I tell him what she says he gets mad at me and makes excuses for her every time for the things she says. I know she is trying to wedge in between us but he doesn't see it. When she found out we were getting married she freaked started saying oh I wanted to get married and you never did and that she didn't think we were that serious. I don't want to lose him but I want her out of my life. I'm stressed and don't know what to do can anyone help?

so last night he came home and said he had all day to think about itand he is going to block her number on our phones. now to just see if he actually does.
well nothing happened. but last night I had enough and I snapped and well now she is taking us to court for the house and the truck. I can't deal with this anymore as I am 5 months pregnant and wish this and her sh*t would go all away.