How do some of these people find mates?

I was out with a friend and her husband this weekend.  We had a bit of a drive, so there was some good conversation on the way home.  We were talking about this mutual acquaintance and how frustrating/annoying she can be. 

She's a runner, a pretty good one.  But, I don't only know that from local races we've run.  I know that because she constantly brags about herself.  Like, all the time.  "I could have won that race, but I wasn't feeling well."  "I won, but didn't run as fast as I wanted to.  I could have gone faster."  "I won that race and they didn't even give out awards.  Can you believe that?"  She is so fricking competitive.   

OMG.  Yes.  We get it.  You are incredible.  Amazing, really. 

How do I know she says these things?  Well, I don't really socialize with her, at all.  But, I have gone running with her in a group and one-on-one before.  And, when you run with her, you don't talk.  You pretty much just run and listen to her go on and on and on and on and on and on about how great of an athlete she is...or that her kids are the best at this and that.  So, the run can feel incredibly long.  And painful. 

I've distanced myself from her and rarely see her that much, or run with her.  She probably hasn't caught on and would never guess my reasoning. 

Anyway, she's married, with kids.  And honestly, she has to be one of the most insecure people I know.  Anyone who brags about themselves that much, has some insecurity issues.  Big ones. 

So, let's start with my question in the title of this post.  How does someone who is incredibly insecure find a mate?  How is their insecurity attractive?  How does that draw someone in?  And, she masks her insecurity with bragging about herself.  How does THAT draw someone in?  Either way, I honestly don't understand how she (or others like her) is married.  At all.  And, from what I heard, her husband can be a prick, but still.  I don't get it.

And the thing I've always heard about myself?  "You can be intimidating."  "You're confident, which can be intimidating."  "Your height can be intimidating."  (FYI, I'm not an amazon, but I'm tall)  "You have your sh*t together, which can be intimidating."  "You're so independent, which can be intimidating." 

OMG.  So, I'm being penalized for having my sh*t together?  Are you effing kidding me?  I'm a broken record, but I DON'T GET IT. 

I'm so sorry that I come off as confident, not arrogant.  I'm sorry that I'm tall and can't really change that.  I'm so sorry that I am successful at my job and haven't made a train wreck out of my life.  I'm so sorry that I'm independent. 

Are we to believe that if we have low self esteem and feel the need to build ourselves up in front of others, that we'll look attractive to others?  I don't buy it.