My relationship with my brother in-law is in question

I recently lost my best friend to a case in which they chose wrong. I am 26 and recently started dating a woman a few years younger than me. She's sweet, charming, in my eyes perfect. I am on a good path to become a doctor and earn a good lifestyle to raise children. Then I found out my cousin (1 year younger) was dating my future brother in-law. I have no issue with that and initially my family was acceptant of it. Everything seemed to be going right for everyone. A month later my cousin's mother finds out and accuses me of arranging the relationship. Then my future brother in-law's father accuses me of allowing the relationship. They didn't blame the people in the relationship.<br><br>Fast forward a month, my future mother in-law goes silent on me. My cousin and brother in-law start getting shit from their own families. I try to talk to my future brother in-law and cousin, but they say they are too afraid to reveal they are in a relationship in case they face the same backlash as I did.<br><br>I need advice on how to save the relationship I am in. This is important as my future wife has a foggy way of thinking from growing up in the darkest of environments, in case my in-laws try to manipulate her to believe I was the cause of the backlash. I am also worried I won't be able to save the relationship between my cousin and future brother in-law.