Sounds like your friend is in an abusive relationship :(
She has a long hard road in front of her.
I hope I'm wrong.
But unless her family is toxic & abusive... And Beaux is just giving her the strength to stand on her own... Isolating a person from their family & friends is usually the 2nd or 3rd step in the abusers' handbook.
Why am I focusing on your friend?
Because 99:100 its not about you, at all.
Its about them.
Just like when YOU pull away from people, it usually has nothing to do with them. School, work, marriage, parenting, moves (geographically & socioeconomically)... These & others are all major life events that create changes in our schedules/ daily lives/ availability.
So... I won a personal bet with myself.
You know when most parents "look up" and realize they don't have friends?
When their youngest is 2 or 5.
Because we've been busy.
We might have a couple friendships we've maintained through infancy & toddler years... But most get so wrapped up in all the demands of family that its not until age 2 that we start having more time to ourselves, or age 5 when they're in school & we have "real" time... That we start wanting friends friends again. Not just play dates, or the occasional girls night... But the "it takes hundreds of hours, call any time, hugely devoted" friendships. Foundational friendships. Which take energy & time most parents of toddlers just don't have.
Am I saying this is really all your fault?
Nope.
Just a contributing factor.
Most likely, you were too busy to devote that time/effort into more than a couple people. Now... One of those people has gotten busy in her own life, and you're feeling the loss really keenly in your own life... Because you don't (currently) have other friendships to expand in the gap.
Don't worry.
If what you WANT is a confidant, close circle, large base... Whatever... You'll fill that gap now that you have time and energy to miss it.