First off, I am very sorry you're going through this. It does, indeed, sound like a tough and chewy time, but it's most definitely not wrong.
Secondly, everything's coming from a (moderately) cis straight guy, I really don't know how this situation would play out beyond guessing and imagining, so I apologise in advance if anything comes off as irrelevant, off-key, or even insulting.
To get on with it, the two things I know you shouldn't do right now are the following:
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Do NOT change who you are for someone else, especially not before you've even broached the subject with said person! Not only are you risking dumping yourself for something which may very well go nowhere, but you may actually dump aspects which the other person would enjoy. Always bring yourself, as you are, to the table. And always keep at least 10% of yourself for yourself.
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Do NOT get involved in anything until the divorce paperwork is signed and stamped! This is skipping a few major steps, I know, but right now everything should be off limits. It'll just end up becoming a bigger mess, believe me. Plus it wouldn't give you the best start possible, which you already kinda' have through the fact that you're very close friends by the sound of it.
What I would do, in all honesty, is nothing. At least not now, not until she finalises her divorce and has some time to grieve and recover. The best thing you could do is continue being there for her as she goes through The Suck, continue being her friend, that's more valuable than anything right now.
Afterwards, after you've also had some more time to process things, cross the t's and dot the i's, so to speak, you should consider having a talk about it with her. Present your side of things, explain it as best as you can, try to frame it all as "here's where I am, this is what is happening to me." It'll probably be a lot to process for her (or maybe not, but those odds are not worth the bet), so try to put as little pressure on her as possible.
It may make things awkward between you for a while, it may even lead to the dissolution of the friendship. If the latter happens, well... maybe that friendship has reached its natural end. If the former happens and you are absolutely certain you can play The Friend while pining for The Lover's role, then business as usual - be there for her as and when she needs it, give her space to come to terms with the new data, and see where things go.
But, again, no changing who you are! Seriously! As long as you don't have profoundly toxic and/or damaging behaviours (which are a whole different conversation), you should never give yourself up for somebody else! Dating hollow flesh defeats the purpose.
Yeah, I get it, believe me... Have a similar situation on my end, with one of my oldest friends. Luckily, it's very easy for me to be her friend and keep things platonic (with the occasional mild flirty poke), so there's been little turmoil. But I did go through another one of these earlier in my life, and that one was just pure anguish. I had to distance myself from the situation after a few years...
Spoil yourself as much as you can right now, besides dampening the impact of things, it'll also serve as a reminder that you can also offer yourself care and attention.
And you can hang on to that love, but I think it needs to fit between very specific points on the intensity/complexity/whatever spectrum in order to be able to comfortably juggle being friends and keeping things in check. If you're there, you can still offer the platonic bit of that love to her. It really does sound like you've fallen hard for her and that you genuinely care about her, and genuinely loving someone for who they are can never be a bad thing. It can be friggin' uncomfortable, sure, but it's never bad to love.