Dealing With Husband's Ex (long post, kind of needed to vent)

My husband and I have been together almost 3 years and have been married for just over 2 years. He has a 3 year old daughter with his ex fiancée and we have an almost 3 month old son. I have been around since his daughter was 6 months old and his ex has never liked me. Even before she met me she hated me. She's always disrespected me and has talked trash about me to my husband. The first time was when I first met her and their daughter. He and I didn't show any PDA out of respect for everyone and I did my best to not hover over my husband (which was hard because it was his ex's family's Easter party and I didn't know anyone but him). The very next day she started saying she wants her family back and started talking trash about me. Things cooled off and then fast forward to July 2014 when he and I got married. She got upset because we got married just a few days after their daughter's first birthday so she thought we were taking the spotlight away from their daughter and she blamed me. I didn't choose the date. He's in the military and had to move so we got married (we were engaged, it wasn't spontaneous) a couple days after I moved to where he was. Fast forward to November 2015; we found out we were pregnant. She BLEW UP! She said I trapped him, I tricked him into getting me pregnant because I was "jealous they had a child together so I wanted one with him", and also said I was only with him for money. When we got together he had no car, was living with his mom, and had no job except for drill every month. I didn't care about money but she was going to do and say anything she could. She was still telling him she wanted her family back up until a week before we announced to his daughter that we were having a baby. She blocked me and started talking more trash about me to her family (her mom was so supportive and nice to us, thank goodness) and to my husband's family. She was really angry because I was due just 3 days before their daughter's birthday so she had it in her mind that I planned it that way. Things cooled off when we found out the gender and she became supportive and sent us baby clothes. She had a baby boy so she had plenty of stuff to give us still. Things were finally really good, until I told her she wasn't invited to my baby shower. I wanted my stepdaughter there but I had to miss out of having her there because the ex said that my stepdaughter wasn't coming without her. She was rude to my parents and last thing I needed was for her to say something around the rest of my family (she has no filter and doesn't know when to not say inappropriate things). And then there's the present. She is now angry with me because I refuse to tag her in pictures of my son on Facebook. I usually get tagged in things of my stepdaughter but now I don't because I won't tag her in pictures of my son. My husband is on my side and won't tag her as well. She says it's not fair but I look at it this way: I am another parental figure to their daughter so I should be involved in things but she is nothing to my son. She doesn't need his pictures. She said it's because she wants to show my stepdaughter the pictures but she can just go to my page and show her plus we FaceTime almost every day. It's to the point that she and I just ignore each other. But I am being left out of things that have to do with my stepdaughter. I still am not going to give in to her because I'm tired of having to make her happy and that's not my job. She needs to learn that she can't get her way. She's the ex now, I'm the wife.