I may not be much help, because I feel very different from you. There is no way I would want a new partner at the funeral of someone important to me. I want to be with the people who knew the person who died, so we can all grieve and tell stories and laugh and support each other. Having to escort someone around who doesn't know the stories or anyone else there would make no sense to me.

I've continued seeing other people during all of this. Maybe I should have stopped...maybe I should stop until I feel less guarded around my current partner.

If you want polyamory, no, you don't stop seeing other people while you wait for one relationship to resolve. You learn to balance multiple relationships that are at different stages, and to give each relationship the effort it needs in the time you have available and build it up over as many months or years as it takes.