C.

We met Freshman year in college through a mutual friend, which turned out to be only the first of a million common threads and coincidences that bonded us together instantly.

For one, I worked at the cheesy heartburn-inducing Faneuil Hall Mexican restaurant right across from the chic clothing boutique where she pulled in a big $4.25 an hour. I served her illegal margaritas and she hustled me into the line-out-the-door nightclub with the stupid beach club theme, which connected to her shop by a surreptitious back staircase. After one wild night out with the (much) older and (very) cute managers, we swore each other to semi-secrecy, and our friendship was sealed.

The time she almost fainted on the Boston T, I ushered her off the car towards to a low wall bordering one of the university buildings. She lay down, and then I lay down head to head with her so that she wouldn't feel at all weird lying down on a wall in the middle of the day.

Or maybe that was something she did for me. It's hard to say; we blended together at times.

I always loved that could turn any negative into a positive: I gained weight. You actually look better. I started smoking again. I'll help you quit whenever you're ready. My hair color accidentally turned pink, ugh. Let's hit a club and work it!

Our support for one another continued into our twenties and early thirties, when we never lived more than ten blocks apart. We traveled together. We partied together. We traded clothes and furniture and just-because-it's-Wednesday gifts. We consoled one another's breakups and celebrated our accumulating career successes over much wine. She turned me onto Port and acupuncture and London. I turned her onto Prada and Manhattan haircuts.

In our single days, we spent Valentine's Day dinners at quiet West Village restaurants where same-sex couples were treated with appropriate fanfare. In our coupled days, which rarely coincided, we turned dates into trios. Our visiting parents would never think to plan an evening at the theater or dinner at the Oyster Bar without including both of us.

This is what we have in our single 20s, if we're very, very lucky.

Then came the serious relationship (hers), the move to the burbs (hers), the first kid (hers), the move to the more distant burbs, the elopement (hers) and then our first ever fight in over a decade of BFF-ship over, essentially, the acknowledgment of what I'd sensed for some time - that I wasn't on top on her husband's list of favorite people. I doubt I was even in the top 200. I felt left out of her wedding plans. She felt I was raining on her happiness.

It wasn't a breakup entirely. We talked, we worked through it. But the reality was that two rivers weren't all that separated us now.

I had Thalia at the same time she had her second daughter - we gave birth on each other's due dates, and soon found ourselves in similar mental spaces again. Her joy at being able to share the experience of parenthood with me was palpable, and she was generous both with her time and her council. We reconnected. We celebrated again.

Now when we get together on the rare weekends that our schedules allow for, there's too much to say and never enough time. We talk far more quickly than people should be allowed. We talk with our mouths full. We talk over each other and hold two simultaneous conversations, remarkably still able to take in every word. I always leave feeling psychically nourished and happy.

Earlier this week we spent more real time together than we had in a long, long time. The hours led us to the deeper conversations, past "So how was your week," past "Yeah, my kid has a cold too," past even "Hey, remember the time when we..."

We got back to the connection that reminded me why I have loved her so much all these years, why old friends are such a commodity, why women need other good women in their lives.

This time when she slipped out my front door towards the elevator, my heart hurt terribly.