We're Like BFF's, You Know!

I've been thinking about something for awhile now. When I say this to my husband, he gets very nervous. :) I've probably overtalked it to him so now I'm voicing it to a different audience. I haven't got it all figured out, and I feel like it will take me awhile before I do. It's the whole concept of friendships.
You always hear about how there are different friends for different seasons in your life. Totally get it. So...what are friendships supposed to be like when you're in your mid-30's, work, clean, cook, and stay busy with three kids and all that goes with it? How do you find the time to work on the friendships in your life that have depth and meaning? How do you let go of the ones that aren't really worth hanging on to? How do you find quality ones when you are put into new scenarios in life?
I have to admit-sometimes I feel like I fit in everywhere, and yet I don't fit in anywhere. I can be surrounded by people and yet feel totally and utterly alone. I have many friends, and yet when I get a rare opportunity to shop or get a pedicure...it's usually by myself.
I look back (that makes me feel old to say that) and look around me now and see so many different kinds of friendships in my life. And really, it's probably a sampling of the friendships we all have in life....
...the college friends who you will love forever. They get you and you get them. No matter the changes in life or the distance between you, it takes one phone call or one email, and bam...you pick up where you left off. And it is oh so good. And oh so far away.
...the couple that you bond with (we like both of them!!!) and feel an instant connection. Kids play well, you love getting together...and then they move away. The ache when they leave-it never really leaves. Long distance relationships are hard but totally worth it.
...the fun person who is married to a dud. Admit it, you all have one of those in your life. You can get together one-on-one but the couple thing isn't really happening.
...the friend who is a little too judgmental, or too opinionated, or too negative, or too materialistic, or too holy. Lots to like but slightly irritating too.
...the friend that your inner gut tells you they are probably badmouthing you behind your back. You think you're crazy for thinking it, but you are probably not.
...the friend who is popular and has lots of other close friends so you don't want to stalk them because you really really like them but don't want to appear too desperate to hang out.
...the friend who is closer friends with your other friend but yet the three of you don't really hang out together. Kinda awkward.
...the friend who thinks your husband is a little weird or off the wall or loud. They invite you out for coffee, but you don't get invited to the couples kind of thing. Goes both ways, I guess. Whatever. He's a rockstar.
...the friend who you really like and would love to be closer to, but they keep you at arm's length.

Can anyone relate?!? At the end of the day, I sometimes think...how many of my friends can I be totally real with? That I can cry to (like the rare ugly cry) and be gut-level honest with. For many of us, we have a spouse that is our best friend. They have seen the good, the bad, and the ugly and still love us no matter what. But sometimes you need that girlfriend to go shopping with, get a pedicure with, talk about Grey's Anatomy with (seriously...the plane crash was sad), talk about mothering failures, and how you want to be a better person. Not quite the hubby's territory.
I have an awesome husband, an awesome mom, and a handful of awesome friends that have my back and love me for me. I couldn't do life without them. But I'm not sure at this phase in life, (when your personal stuff sometimes takes a backseat), how do you start new friendships, maintain close ones, and grow them deeper? Like I said....I've been thinking about something for awhile now.