@confused83 :thinking_face: Hmmm .... this raises many questions due to the lack of info you have supplied. How long has this been your husbands ex wife for? We they friends since you have been married? If so, how close were/are they?
Are there children involved? Did you ever know of get on with his ex?
Without answers to these questions, and possibly more I couldn't suggest much since generic advice or thoughts probably would be of no assistance :/