My girlfriend hates my best friend. What do I do?

You girlfriend seems to using child like tactics to get your sole attention and if she is also emotionally abusing you, yes thats right EMOTIONAL abuse, by throwing tantrums, using bad language, and being violent, then honestly you should get rid of her asap. Forget marriage, it wont last, she seems like she needs therapy or anger manatgement. Marriage children hormones will make it ten times worse she already sounds mentally unstable. Your friend does NOT seem malicious, just a bit child like and at least he does apologise. He helped you when you needed it, thats a big thing. I'd say dump the girl and stick with your friend.