I like #3 because, you are (possibly) not ready to visit the discomfort of the other options. I also think writing will help you not AVOID the issue as option #1 could allow.

Dissociating may still be helping your survive, but I think eventually, your t will have you confront this in baby steps. Even if this results in switching. Are you still dealing with trust issues with him? I ask because, I feel like you are if you are afraid to switch. Have you told him this? I'd love to know his response to your fear on this. I wouldn't worry how you come off to him, although i do the same. But, once the trust comes into play, switching could (maybe) be a great way to start working through some issues.

I am perhaps, not the best judge on this, I'll admit, but from a viewpoint such as mine, one of hearing your fears, I would think to be "free" in session, to dabble with the experimentation of letting yourself go, well couldn't that be a positive thing?

Umm, back to option 3- I like writing because I can spend as much time as I want and tweak the words and feel I've commanded some control over how the information goes over, I can walk away when it gets intense and I can pummel through the words at any pace.
Ultimately though, writing means you are visiting these issues, you are not avoiding and you are bringing them to the fore-front even if it's on your own. I think this is good. You clearly express yourself incredibly well through written word. I am always amazed at the clarity, insightfulness and attention you have to detail. If you are in any way, this articulate in person then wow! Cool and fantastic!

I also think your last post here really speaks of your fears and maybe you could send it off in email or something in this way as you just did.

So, I suggest the writing because you can maintain some semblence of control and reach the boundary thing in a comfortable place without "eyes" on you or switching with him there. Then send it off-poof-your words in the universe.....
Yes, intimacy and love and all for that which we yearn for from this dyad we pay for. Funny, no other relationship will/can replicate this in society so they say, and yet they want us to react to them as we would anyone else so they can help us with the world and relationships "out there".

Transference, is it necessary? I dunno, but you have it or you don't you, accept it or you fight it (or teeter between both acceptance and fighting like I do). I think I'd rather have it and work through my issues with it in the therapeutic realtionship, than sit across from some rigid person I don't care for. If it tricks me into dealing with issues, then so be it, and if I have a ethical t (which I'm counting that i do) then she'll help me through it. I tell her I wished I didn't care for her so much and she tells me, I'm glad you have this problem. It may be uncomfortable she says, but this is a good problem to have here with me, we will work through this and it's ok for me to be in your head, one day I'll be there mush less, but for now, it's ok.

(*sigh) I've never felt this way in any other relationship. it's terribly confusing and upsetting and wonderful and intoxicating and vulnerable and scary....

One last thought here, why do you think your t would possibly "freak out"? I recommend not being afraid to say how you feel and what's up with the boundaries for you. He should work (responsibly) to deal with them, WITH you. If you censure yourself, you aren't giving him everything to work with, and then it's you batting this around with yourself.