Hi TidalYuri!
I can't give you the answer you're looking for, but hopefully some of my own experiences will help alleviate any sort of worry.
What you're mentioning is what I like to call the "Disappearing Act".
I've been roleplaying for over 10 years now, and from my personal experience - this happens ALL THE TIME.
I find it most often happens with roleplayers whom have not held an account for very long, such as is the case with your missing partner. She had been active for under a year when she vanished. Normally, I think that it's easy for them to disappear because they are not socially as active in the forum as they are newer (they as in, people who vanish). Another component - that I've seen on different sites - is the notion of having an itch/craving to write/rp/fantasize so members create accounts to scratch that itch and then when they feel satisfied or when life gets too busy/they can no longer keep up, they vanish. The longer you stay away, the harder it is to come back for various reasons (shame, embarrassment, dread, loss of interest, etc, etc.).
Although I find this happens most with newer members on the site, it does in fact ALSO happen with longer-held accounts, too!
I, for one, have vanished before. And I've done it a couple of times.
1) Once, real life and personal issues interfered with my ability to write and I lost interest and passion completely. I didn't want to tell any of my partners because it had come out of the blue, and I was also partially in denial that I had lost interest in BMR, as well (since I'm on normally every day). I stopped coming on less and less, and eventually, stopped coming altogether.
2) Another time I disappeared was due to a severe concussion. I lost the ability to read and write properly for a long, long time and took months to recover. I wasn't allowed on the computer and staring at anything electronic for more than a few minutes was extremely difficult and painful. I returned months later, apologized and explained my situation, and was greeted with welcoming members who supported my recovery and were VERY patient with my roleplaying (as the quality of my writing had deteriorated, not only because I was out of practice, but because symptoms of the concussion were still present).
There is good news, here, though!
So far, in my experience, they almost ALWAYS come back and reach out at some point. HOWEVER, that is normally followed up by more inconsistency and sometimes more vanishing, but sometimes... Just sometimes... they come back for good!
I had one of my favorite partners disappear on me and I was WORRIED SICK because we had fantastic communication and whenever something was up, we always communicated. Until he stopped logging on out of the blue... and disappeared for MONTHS. I thought for sure he died. FOR SURE. Or was dying/sick/something horrible, because I'm paranoid like that and a total worry wart (even though I've done this myself... hypocrite, I know). But he didn't. He was very much alive but real life had kicked in and kicked his ass, as what had happened to me. He eventually did return to BlueMoon and returned to our fantastical RP, which was a blessing. But keep in mind, this doesn't always happen.
She may also return and not want to RP at all. She may lose interest after all of this time, too.
ALL IN ALL,
If you made it to the end of this convoluted post...
All this to say:
DON'T SWEAT IT.
Life happens. Shit happens. She is most likely fine and if she isn't, well... nothing you can do about it anyways.
My advice is to move on. So long as you're stuck up on the idea that she will return, and/or so long as you place her/the RP on a pedestal, you'll never find someone just as good. BE OPEN-MINDED! Stay positive and keep searching. Who knows, you may even find someone better!
All the best from a person who has both worried for a disappeared partner AND ALSO BEEN THAT DISAPPEARED PARTNER. Cheers!
~ Tempt