How do you deal with psycho mother in laws?

I always dreamt of having a good relationship with my in laws... Every time I dated someone their family loved me so I never thought that would ever be an issue for me...

Funny thing is my in laws use to love me... My mother in law and I were on okay terms at least... Until my husband and I got married. Then I was a every name in the book and basically the spawn of Satan himself... I did nothing to her!

My brother in law and I got along great called me his sister and would talk to me all the time about advice for his relationship... All of the sudden his gf decides she wants my husband and not my bil and gets in good with my mother in law and they have ever since been trying to cause issues with my husband and I so we divorce. My mil has even said she wants my bils of to marry my husband and I can marry my bil to "stay in the family if you want"....needless to say with all these issues and fighting now my bil hates me as well as my mil and a few other in laws... We have the proof of my mil and bils gf as they have said "we will stop at nothing until you two are divorced" and all we've done is nothing but stand up for our marriage and love for each other... And have cut these people out of our lives which caused more issues...

I don't know how to deal with this... I feel horrible because my husband and his best friend/brother no longer even speak to each other...

I feel like all this is my fault but at the same time I didn't do anything...

How would you deal with this? Would you continue to try and make things better or just give up and accept that your in laws will never accept you and be apart of your lives?