Don't worry bro, as a kid I asked my mom on the phone if it was true that she was seeing other guys cause my dad told me so (she was) but that turned into a big fight and my parents got divorced... but on the good note neither of them remember this happening so even I feel like I am at fault they clearly didn't think that was the tipping point and it was other factors that led to my family falling apart.
My point is they are probably fighting based on factors that you did not contribute to so don't feel sad!

I think our family will fall apart because of me. I didnt know telling the truth would cause me such mess. I basically told my aunt that my grandma knew my uncle was having an affair but she liked turned a blind eye cause grandma hates my aunt. And now they are fighting and I blame myself