uncomfortable

It was my step sons birthday party today. I wanted to go but in doing so I would have been hanging out with my husbands ex wife and all her family. It would have been very uncomfortable for me. She doesn't like me, though she did say I could come. She said she's wanted to meet me and every time we've been around each other at his daughters dance recitals she doesn't look at me or say one word so we've never officially met. We have our reasons for not being comfortable around each other but that's a long story so I won't get into that. I feel bad for not going but at the same time I didn't want to be in a room full of people who I feel were just going to judge me the entire time. It would have been easier to go if we have actually introduced each other in the past but we haven't yet and I didn't want that happening in front of her family. Is that wrong of me? I'm new to all this step mom stuff and dealing with ex wives are super hard. My husband understands that I would have been uncomfortable so he's not mad or upset with me but I still feel bad...ugh. I just wish that I had that understanding relationship that a lot of ex wives and step moms do. But I don't. So it makes it that much harder. So is it wrong of me to not go because I wanted to avoid being put in an uncomfortable situation? Do you think it will get easier as time goes on?