My Best friend always comments on my relationship. She puts it down and twists what I say to make it negative. She wants me to break up with my boyfriend.
Is she jealous?

Maybe you guys should sit down and talk about this, you will get a better answer if you ask her. Just be honest with her and find out what's up.

Of course she is jealous! She doesn't have as much attention from you because of your boyfriend. Talk to her and reassure her, and politely tell her to stop the negative talk. Maybe she doesn't like him period. Talk and listen, that's what real friends do.

I don't know if jealous is the right word.

Maybe insecure?

Were you very close before the relationship?
How long have you been going out with him?

As it may just be an adjusting period.