Search Results: sleeping with my best friend

I just witnessed this:

Two guys are friends. They're in the same circles. Not best friends, but close. New girl enters.

All three people are above average in looks though their morality and sexually-driven motivations are pretty suspect. They're all sleeping around a lot.

Anyway, Guy #1, the bartender manager goes out with girl first. It doesn't last long. But they're really into each other. Coworkers talk. He's been sleeping with the staff. He's evasive and non-commital. He's ghosted, jumped around. Some girls warn the girl about him (although some of their motivation is jealousy, as well.) But she's an independent girl, and she doesn't like being told what to do. And, she thinks she is/wants to be special. She goes out with him anyway. They hit it off. Apparently more than with the others. After a short time he asks her, "You wanna be exclusive?" much to her surprise. She is happy. "Yes."

But before things really get going, another third party [helps her out?] by showing her a pic of him with another girl. On a date in a lunch place. She gets pissed. "I thought we were exclusive. You're already sneaking around on me?" "No, that was before. Before we decided. It's over now." But she doesn't believe him, breaks up. Then quickly changes her mind, asks to get back together. He: "No, I don't like the drama." He's also apparently upset about her not trusting him, and listening to outside influences.

Shortly after, she gets asked out by Guy #2, personal trainer. They also hit it off. She likes him "Even more. He's a man, not a boy." Trainer asks bartender friend, "Hey man, you ok with this... if I date her now?" He doesn't say much. He doesn't want it to happen but feels he can't intervene. Time goes by, and now and now guess who comes back? Bartender: "I just want to let you know that I care about you. I want you back." Huh? "I was scared." Of what? "Of falling in love, getting hurt."

I've been friends with my bestfriend for over 10 years
We are the same age (25)

I've had 3 relationships
she's never had a boyfriend

she's met all my ex boyfriends

She always tells me that she's not into relationships
So she has one night stands/friends with benefits
Never met any of her guys

But she is bisexual
So she's hooked up with guys and girls
she's kind of a tomboy

I've had some messy breakups
And in every relationship, there's always ups and downs
Its normal
Since she's my best friend, I tell her whenever Im going through relationship problems

But what annoys me is that.. she's always negative about relationships and guys when she's never had a relationship before

She would tell me like:
- oh guys are such idiots/always just want to f**k
- all your relationships are shit and never worked out.. thats why I dont want to be in one
- marriage will never work out, I dont know why people get married
- I love bad boys, I always fall for them
- judging from your relationships, all guys are not worth it
- I dont want a relationship, so Im sleeping around.. so much better
- why do you date gym guys? They are all f**kboys and messed up

It just annoys me when she says those things

I've known my best friend since childhood

she's 25 and never had a boyfriend before

But she always tells me how guys would flirt with her at the bar
Or
Guys saying "damn sexy" when she walks past them
Or
she's sleeping with random HOT men

she's never introduced me to a guy
Or never seen a guy go up to her

Should I believe her?

If she's lying, why would she lie?