Ohh, the exes coming into the house, I've got 2 of those.
When SD was 9.5 and was spending Sun to Fri at our house during the summer, her mother who had to be in our town on Wed, decided that she will go visit her. So every Wed of the summer, she would tell DP that she'll come, nobody would tell me anything, and she would get a tour of our new house, usually with some friend of hers, happily talk to my DP, her daughter, my son, or any other guest we had at that moment, but pretty much ignoring me (other than a cold hello). Why the f#$% did she have to enter our house if she didn't feel good with me? My DP told me that she has the right to see her daughter whenever she wants and doesn't need my permission, that she was shy and I should have talked to her myself (I tried, but hard to talk to a person who never looks at you and just talks to others). This caused a lot of fights between us, but it never occurred to me to close the door in her face because I didn't want to upset SD. I was flamed on here a lot for being a wicked SM (by Sandy2K also), but I sucked up some shit from their mothers in order not to upset the skids. It was always done passively aggressively, so if I ever said something, I would be the bad one there. If they were agressive, I at least could have dealt with them the same way.
So in response to her visits, I started entering her house at pick ups (before I was respecting her territory) and she complained about it to someone we both knew. She would welcome my DP dressed up in a sexy satin night gown at 9 pm. I have seen her in sexy short dresses with cleavage (she was in her early 40s) without a bra...But I still never showed anything to my SD because I knew how much she loved her mother.
Ex#2, after a fight with me, tried to come to our house to pick up her son (she never did it before), 2 weeks after I gave birth, with her new boyfriend and his adult son whom I've never met, to meet our baby. It was allowed by my DP. We had a fight and SS (15 at that time) thought that I said that his mother had to wait in the car. He declared that he hated me and stopped talking to me (and coming over) for months. I basically had to apologize to her to keep the peace. Otherwise, I was the mean one who didn't understand that my DP and his 2 exes get along.
Honestly, the ex in your case seems harmless. She might be shy, not social and probably not responsible for her partner being rude to your DH. I do think that in your case, you could be a bigger person and not be affected by this, especially since your DH is on your side and that's the most important thing. Mine wasn't.