Parents getting a divorce... Help..!?

At first I didn't care because my dad was so rude to my mom... My whole life. (I'm 15) he finally gets that she wants a divorce.. I now feel bad for him.. He was crying, saying how much he loved her. It makes me sad, as pathetic as he is I love him. I'm mainly worried my mom will date when they divorce... Even though she told me earlier she just wanted me, my sisters, and friends.. She's completely different. I don't like it. I'm so depressed... I don't see why she is already interested and she's not even legally divorced. Our relationship has plummeted because she texts this guys (she obviously likes) and I make it a big deal. She put passwords on all her things.... I'm so alone :(. (my sisters are in college)