Why is my friend trying to fish out negative information about my relationship?

[CB2929A]

So my friend met my boyfriend the other day. She is single and I’ve been with my boyfriend for about a year. After my boyfriend left I went to stay with my friend. The entire time I stayed with her she said negative things about him to her mum. When we went out together she kept grilling me for information about my boyfriend that was negative. She kept saying “do you think he is like your other previous boyfriends who were abusive?” And kept fishing for information to make out that he was a bad guy. On the same day she kept talking to me about an abusive guy she’s been with in the past (this has been her only relationship). She also told me that she had researched him and had been on his profile the minute she found out that we had got together

Why is she so obsessed with my relationship?

[Guy13]

Yeah, this girl is trying to get information to use against you still. I know you did that and I would never do that tou you (boy) or myself (your "friend"). Yeah, she listened to you but couldn't believe it... nor the names and things you said about him... you poor man-you deserve better than her (you)...

That's where this is going. I would back away from her "friendship".

[Wise4myage]

She has her eyes set on stealing your boyfriend.

[Qinart]

Could be jealousy if she is all over your relationship but it's difficult to tell. It depends on how she is talking, tone, words etc.
You could ask her straight up with a clear mind though

[HateyouxD]

She cares but a little too much. Say, homie back tf up a bit