FWIW, (For What it's Worth), I don't think this is passive-aggressive at all. My understanding of that term is this: if you felt this and didn't didn't
write the note (i.e., passive via doing nothing but having a feeling or need) and express your needs of limited contact...the next step in the concept would be if he violated this boundary and still
you said nothing, but then, you got angry about it, but still said nothing...but let him be aware you were angry in other ways. Retalliation.
In my point of view, your writing such a note would be proactive and setting boundaries that you need to heal.
Passive-aggression as I understand is hiding how someone really feels and letting it build up via resentment, sometimes over time, and then BAM!-letting a person "have it", so to speak.
I think leaving it so you're not there after he reads it is also a boundary or form of self-protection and necessary if you think he will spew or twist.
Good luck on your move. DD and I may be doing that, as well.
A person is a person, no matter how small. -Dr. Suess
Perserverance and spirit have done wonders in all ages.