my aunts husband of 17 years is cheating should I tell her?

I found out my uncle has been cheating on my aunt and I'm not sure if I should tell her?

I grew up with my aunt being my best friend, but now that I have developed and become a beautiful vibrant woman she has shown many signs of jealousy. (It's very obvious due to things she says ect. and I hate it. I don't want her to feel that way I've gone as far as to stop wearing makeup doing my hair and wearing tight clothes around her) this is what makes it extremely difficult to decide what to do. She is in her forties and she I know she has many insecurities. I don't want her to feel that way and I don't want her to lash out towards me for telling her. Here comes the hardest part. My uncle is not a blood relative and we've never talked much he's been there for my family when we needed him but he's always been reserved and quiet. He recently hit on me one night over the phone, offering me $500 for naked pictures. He apologized for it a few days later blaming it on mixing alcohol and medicine but I know he is probably paying women for things like that. It seems like an addiction or something. I Haven't slept well because I don't know what to do. I feel like she will blame me for it because she always blames me for looking the way I look when guys hit on me. Shes the only person I have family wise and I don't want to loose that but i don't want her to constantly be cheated on but I have to think of the outcome as well. it's hard to find a man when you are in your late forties in this area because everyone wants younger women instead of a beautiful smart and classy aged woman. It's sickening how I havnt met one man in this area that hasn't cheated because it's the new normal everyday life. You'd be suprised! I don't know what to do...please help!!!