Best friend doesn’t like boyfriend

I’ve never really had any luck with relationships and have been screwed over pretty badly in the past. I just recently reconnected with my ex and we’ve really been hitting it off. The only issue is that my best friend doesn’t really like him. She always has my best interests in mind so I’m not sure how to feel. It’s just that she’s never really met him so I don’t know how she could already not like him and now I’m conflicted