Want Sis In Law Bad

I cant help it but I have wanted my sis in law for almost 40 years. It has been hard to not have expressed my feeling with her. I think deep down in side she knows i care for her maybe a little to much. She has always been a sexual type person to me. My wife and I no longer have sex and seeing my sis in law now makes me want to tell her even more that I desire her.