Unreasonable ?

So alittle back story before me n my husband met he got arounf quiet a bit .. but I don’t judge him for it to this day we just keep jt in the pass and not bring it up.

He hooked up with this one girl.. well call her sally. Well him an sally hooked up on n off for about 4years never dated but sally would cheat on her boyfriends to hook up with my husband back then .

Fast foward alittle me n him started dating I automatically DIDNT like her cause she made it Apperant she still wanted sex and a relationship from him and didn’t care I was in the picture. So he blocked her.. well he unblocked her a couple months later cause she needed a friend through a hard break up.. ( red flag I know)

He kept telling me there was nothing to worry about and he would never cheat.

Well he joins the army and came home during Christmas and he saw her even though I said I was uncomfortable with it and he then hid it from me until I saw his location ( red flag again I know) we got into a huge fight about it and he called me controlling and he wanted to see his friend and there shouldn’t be a huge deal about it.

Well fast foward to now we moved an live out of state and he got a 4 day pass to go back home to visit family and everything and the first thing he does is tell sally that he’s coming home and wants to catch up and hang out.

I automatically get very angry cause this is supposed to be a family trip not a trip to see his ex-fling. And he once again says it feels like I’m trying to control him because I don’t want him to go see his friend. And I ask him why is she so important that he has to see her when he said in Christmas that be the last time??

And he said because it’s his friend of 5yrs and he doesn’t have many friends and he wants to see her and catch up.

I honestly do not get why he wants to see her so bad. I don’t think I’m in the wrong for expressing I don’t want him to see her.

But am I being controlling by stating that?