I want to kick my girlfriend out of my fantasy football league
That's really mean. Why does she deserve to get kicked out?
She always sabotages my team. I don't understand why she would do this to me.
I'm sorry your girlfriend is giving you such a hard time, and you are right to just kick her out now. You don't deserve to have your games interrupted like that and she needs to learn the hard way if she won't listen to reason.
She's just mad that I won the ring.
Sounds like your girlfriend is quite salty, but it doesn't justify that she can just ruin your games like this. It's fine to stop her from playing for now, but I feel it would be best to ask her why she is so intent on messing up your games. She might be upset about something you don't know.