I have this like (not love)-hate relationship with FB; it's how my W rekindled her "friendship"with the OM, also. When I first started posting her in March, I was astounded at how many other EAs and PAs began as FB friendships; those types of affairs were called "rekindled" affairs.
I deleted my W not out of spite, but because I didn't want to be tempted to check up on her. Like your H she does not post often, but with her new life that might change.
H 56 W 48 D27,S21 SS25 SS22 Severely autistic M(#2 for both) 9 1/2 yrs. "I've never loved you" 3/7/2011 Separated 8/7/2011 BITS