Thanks, that helps. I like the idea of speaking as though it were just me. That will help me with others who don't understand the alters. My therapist was responsive, and we worked a bit on the issue, and no I am on a break, which I'm actually looking forward to. I think it will be nice to have some time off where we don't go deep into issues for a few weeks.
His favourite saying when I bring up things that upset me (like the feelings of the alter, or my feelings about him leaving me) is to just say "it is what it is" and attach no judgement to it. At first it was hard without hearing the reassuring "it's okay" along with it, but it is easier for me to agree with that, and use it on my own, than validating everything. Just accepting it as the truth for now, i guess.