Man that ending was harsh!!! I guess thats what she wanted
Yeah, and yet it was perfectly reasonable. Dare I say, well-written. Which is why it was so brutal. I noticed there are several endings. The ending you're probably talking about (Ending #4) can be avoided by simply changing the decision you made when you approached her on the couch late at night. There were 2 options, and one of them was to chew her out (verbally), which gives Ending #4. If you choose the other option, the story continues until you reach a typical "Stay tuned for the next version" screen.
There are several pivotal points in the story that changes the entire game. For example, you can have her friend pretty much removed from the story by choosing early on to ask your dad for advice instead of her, and then continuing to shun the next couple of options regarding her. You can also treat your mom like complete shit, which also changes the story and has her show less interest in the family and their scenes (for example, she will not join you in the shower after that 1 three-some scene if you've been dumping on her). It's deeper and has more branches than you'd expect from such a goofy game.