Or did I just answer my own question because it's futile to tell an unBPD person about your own feelings, especially when enmeshed very deeply?

Bingo.
I've found over the years sharing my "Positive" feelings with my wife has strengthened our R/S and has made her more... ."Stable"... ?
"Negative" feelings I work thru on my own... .Journal, T, or on rare occasion with a trusted friend.
In the past when I tried talking about my feelings she seemed to only "hear" ... ."It's your fault I feel this way"... .Even tho I was extremely careful never to assign blame and always used the word "I" and never "you". It always blew up into an argument about how she "feels" the same way... .then would progress to She "feels" this way and what am I going to do about it. (Completely forgetting about I brought it up and it started about "How I was feeling"
Futile... .