Husband checking his ex wife Facebook

How would you ladies feel if your husband keep checking his ex instagram and Facebook page. I have asked before why he is so curious to look at her pics and news and his answers was just to keep in touch with what's going on because we have custody of the 3 kids and we still not done with the legal things yet. Today again he waz on Instagram using his son's account and he shows me a pic of her and her family, I just lost it . I went off on him, I think it is very disrespectful to me and very inappropriate of him to do this since I have asked numerous times in the past to stop going it.It bothers me so much, of course the witch and I are not on good terms and it took me a long time to get my husband to cut ties with her because of her ungoing drama and crazy behaviors. Plus am raising the kids and there no reason of them to chit chat everyday, she used to use the kids to get to him.