You tell her you're separated, people only need to to know what you're comfortable telling them. You don't have to explain your private life to anyone. (boundary)
People who are worth having around you will honor your boundary.
Did you let the kids pack?
About the match photos, out of all the things your H has said or done, this gets me in the gut. (None of it's good but read around,they do seemingly crazy things)
I know I'm going way off the reservation here but I would tell him it hurts you that he put photos or your son that you took on his dating profile.
I'm the photo person in my family, I take them, I look at them over and over, I enjoy reminiscing about past times. It's MY Family's History.
H couldn't care less and I used to resent the fact that there were tons of photos of him and the kids and about 10 of me and the kids. He didn't get it cause the photos didn't mean to him what they meant to me. I can imagine him doing something very similar to your H, because there is no meaning attached to the photos other than they're photos. If the house was burning I'd want to save the photos, he would never think of that. He's not me.
There is meaning for you in those photos and I would say very quietly and calmly, "H, I know you have a profile online and used photos I took of our children (or whatever the case is). This hurts me a lot and I'm asking that you remove the photos from your profile."
And walk away.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss