I assume you WANT to be in polyship and are having a hard time with the transition. (If you don't really want to be doing this, and are just going along with something you are not really willing to do in order to not "lose" him... stop doing it. Not compatible is not compatible. Be friends.)
You seem like you want more responsiveness/nurture from the BF in the transition time. I see where you are trying to connect, but it seems like there some expectation of him to just mind reader your needs after you kinda hint. That's not serving you guys.
Could risk being vulnerable and just ASK if he's willing to provide more support during transition. And if he is willing tell him HOW to tend to you. What behaviors you want him to do / not do. See if that approach serves you both better.
Could go over jealousy
-- esp page 5 and 6 if you guys don't know what to be doing for each other. Maybe think about your beliefs in regards to jealousy
Could go over poly hell
and talk about how to handle those kinds of feelings too.
Could talk it out and make the plan for the "transition time" now that he's seeing someone else -- what that means in terms of logistics, sharing time, health, boundaries, etc. So that ALL of you make it through the "weird in between time" as best as possible.
The "old normal" is gone, and the "new normal" isn't really established just yet. It will come... but you all haven't found your feet yet after taking this new leap. In time, it will come.
Sometimes changes are just challenging to get through. Hang in there.