I just finished reading through your blog. I enjoyed it very much.
Some of the feelings you describe sound so familiar. I had quite similar fears in the beginning after Alec had expressed that he's okay with me starting another relationship: that he would then realise it's too hard for him, or that there would be other complications. Our transition to poly just felt unrealistically easy and drama-free. But I'm starting to trust it now, and just enjoy myself without (much) worrying.
I can also relate to the feelings of exhaustion after spending time with both your loves, and the longest I've had has been maybe four nights, whereas you had three weeks in a row!
I do tend to make myself crazy over whether I'm being 'enough' for both of them, but I'm working on it and it's getting a lot better. Mya is actually coming tomorrow to stay for a week, so we'll see how that goes.
It must be quite intense to live together, particularly 'til you get the room done? Then again, still a bit different from visiting, since you know you'll have all the time in the world..?