Well, BM did show up to SO's nieces birthday party.  My stb SIL called me earlier to say she was coming and that her daughter felt put on the spot when BM asked if she could come.  She was also concerned that I would think she invited BM.  We were bowling and had 4 lanes.  I stayed on one side and BM & SD16 stayed on the other.  SO called out to SD16 but she shook her head no and went over to BM and leaned up against her - buried her head into BM like a freaking 2 yr old.  He ignored it and we continued bowling and laughing.  SD16 finally went up to SO and talked to him - I didn't listen in.  Then she came over to me with a big smile and arms opened.  I stepped back with a not too happy look on my face.  She asked me what was wrong and I simply told her that I was disappointed in her behavior.  That family will have disagreements but you don't cut someone off to punish them.  And I reminded her that she was angry at her older sister when she did it.  We hugged it out after that.  I showed her my new engagement ring - she was thrilled.  Towards the end of the event, BM apparently had a conversation with SO's nephew (he's 27) and she complained that she's never invited to family events anymore, blah blah.  Nephew said he told her, that she was still his aunt but that I was also his aunt and he loves me and wants me around and she'll have to try to get along with everyone.  She claims she tries but that I just give her dirty looks.  I barely look in that woman's direction.  She finally came over and sat down next to me.  Asked if she could see the ring. More small talk then she says she wants to get along and have a relationship with me - without SO being involved - for the sake of the girls.  I only said I would be cordial because I love the girls, etc.  After the 3rd time of saying we can leave SO out of it, I told her - you need to understand that he and I are together and I will not lie or omit anything when it comes to the girls.  She also got in a few digs about him during our conversation, which I ignored - gave no response to it and kept on track with the topic (she said 2 rotten things). She wants us to have coffee soon.  SO is PISSED that she even came to the party and even more so that she is trying to weasel her way into some kind of bond with me.  We talked about it and I told him I will not be speaking to her about anything but the girls and even then, she needs to go through him first.  There's no real reason she and I need to speak and I have no intention of answering her calls.  I think she's going to try to get an invite to our wedding (not happening).  Or she's up to something.