My Mom Is Cheating On My Dad! I Think She Slept With The Other Man?

It was a few months back then, that i realized my mom is cheating on my dad. she was on the phone everyday with him, but when i asked, she just told me that he was a friend. Back then we were in the USA, but right now we came back to our home town Hongkong. The “friend” or hers is in
Hongkong, and so is my dad. So we came and visited my family and everyone we know in Hongkong. Oh right, i forgot to mention that even back then in the USA i have found texts on my mom’s phone, things like “i miss you,/love you/kiss you”. i was really shocked and hurt. I’d always thought i had a perfect life, with everything i want, friends and family i love. but no. my mom is cheating on my dad. the relationship between my parents arent really good anyways, they are sometimes fighting. but sometimes we would all be good, those would be the times i feel really happy. now that we’re back in hongkong, i can see all my family members again. but, my mom can also see her “friend”.yesterday morning, she went out with a bunch of friends, some were girls, but i believe her “friend” was one of them. at night she phoned me saying she wasnt coming home for the night, having a sleepover. this was really strange. since when did my mom like sleepovers? she’s never had one in her life. so why have one right now? so im thinking she slept with that guy. this morning i phoned her asking if she is coming home. SHE SAID NO, SHE’S COMING HOME TOMORROW MORNING! i couldnt take it anymore, like seriously. so i told her on the phone : ” i know you slept with that guy.” she paused for a sec, then hung up on me. does that mean its true? i phoned her again after that, but no one answered. she didnt want to pick up her phone. i mean my mom is a really good mom. she loves me with all her heart. she takes care of me everyday. i love her. but right now, i kind of hate her. i am only 14, why do i have to go through this? this is unfair. why does she have to tear the whole family apart? why cant i just have a good family and a good life? im crying right now. i dont know what to do. please help me.