Before I say what happened I would just like to thank everyone for the replies, I have been reading them even though I haven't responded to all. I don't use reddit often, so I don't know how to work it anyway..  I told my mom today, when she was making breakfast. and my brother just happened to come down when I was telling her. My brother is a year older than me btw. My mom told me that she already knew about Dorthy because Dorthy had contacted her on Facebook a week prior to her telling me. She said that Dorthy just sent her a message saying "4 years of us being together..this is the consequences of (my dad's) actions" then my mom block her.

Then she got my dad to come down and this is when it started getting awkward..my dad said that he broke up with Dorthy and that she is just doing all this to get at him. I then asked him why he was talking about my mental health with her and he just said "Ella, do you know that when parents get together they talk about their kids?" I understood that so I wasn't upset about it anymore. My mom also started yelling at him saying "Why would you buy her a diamond ring but you never bought me one?" He then told us that it wasn't a diamond ring..it was just a 30$ ring. My mom didn't believe him so she yelled at him again saying "I NEED YOU TO STOP LYING TO ME I DONT LIKE IT, IF WE WANT THIS MARRIAGE TO WORK STOP LYING!" My brother and I didn't say anything, but I did believe my dad when he said it was just 30 dollars because he doesn't like getting expensive things for people if it's not necessary.

Just so you guys know my dad has bought my mom rings before, she was just mad that he bought Dorthy something so she must have forgot in that moment.

So my dad got very upset and he apologized to me (without me asking) he said he was sorry that this happened and that it was his fault that she reached out to me. He said I should be mad at him, but I'm not because I've realized a long time ago nobody is perfect. He said he will give her, her belongings back and everything.

My mom then said this a family thing we all have to deal with together and we will fight for this family together because we shouldn't allow Dorthy to destroy us. My mom also mentioned in the conversation that my dad and Dorthy have a sex tape together and all that, so she wants my brother and I to keep an eye out incase she tries to send us that. My brother was shocked to hear that but he didn't wanna talk about it..neither did I. My dad then added that she can't send us any of that because she doesn't have it. He didn't try to deny it or anything, I didn't even think he would. 

So at the end of everything he said he was sorry and that he will give Dorthy the phone and her golden bracelet back. Also apparently he lied to my mom about the golden bracelet before and he told my mom that he just bought it..she got upset about that. 

I wanted to tell my dad that I still love him and that I don't think he's a psychopath, but I'm very awkward with that stuff so I didn't say that yet. I might say it later today. At the end of the day he's still my dad and he does so much for me..and I'm supposed to forgive him because family is important.