Re: should i tell her he used to like me before he married her?theres a reason!
NO - I don't think that you should AT ALL. Ignore them...pretend that they don't exist, if you really cant stand her. Don't bother with them..your life is entirely different from theirs so let them be. If she really bothers you..just avoid her. But, no need to spend so much of your enegery and thinking about her. If what the guy did still bothers you then leave it to Allah...if hes done anything unappropriate..remember that he will be punished for it. At the same time, don't make your life miserble..you have plenty of great thing to look forward to..so dont be held back by a cousin and his wife to bes catty behavior, girl! Move on with your life and enjoy!
and again, i can't stress this enough, DO NOT.