I think I have finally reached the last straw with my sister. from the start of my wedding planning she has shown zero interest (she is MOH) she will sit on her phone not listening or getting involved or if I am talking to my mom about it she will busy herself in another room. She agreed to come to the bridal shop when I was buying my dress (she promised to come and see the dress before I bought it as I had picked it and tried it on on my own, and she would bring my mom who lives next door to her who can't drive) the morning of said appointment (literally the day after she agreed to go) she said it wasn't convenient anymore and wouldn't be attending or bring my mom 
To this day a year on no one has seen my wedding dress other than my FMIL.
It all came to a head back in November when we had a massive argument about her attitude to everything and everyone in general and tears were shed and I felt like things may improve.... they haven't! She lied about having her son so she couldn't attend or again bring my mom to my dress fitting... I later found out she had lied. She has just got with her new partner and they have been together 5 months, they are getting married in Gretna in August and no one is invited and she has now announced that she is pregnant due in January.
If she is happy I am happy, however with this news I tried to have a discussion with her (via txt message which is 99% of how we communicate) about getting measurements for bridesmaid dresses now as I will need to order them in December / January when she will be 8 months pregnant (the dresses just need height measurement measured down the front of the body, it makes zero difference the size of the waist or if she is bigger but the bump will obviously change the measurement I can take from bra band to the floor down the front hence it makes sense to take it now before she gets big) she showed massive reluctance to this. I also mentioned the wedding cars and put it to her that I want both her and baby to be comfortable on the day so can change plans on wedding transport if needs be and can we get a plan in place in the next few weeks so I can book the transport (I will point out I know nothing about her new partner, whether he can drive, if he has his own car so I'm trying to accommodate her possibly needing to be bringing baby with her to get ready in the morning etc) she said that she doesn't intend to discuss wedding plans just yet.... I don't even know what that means? I'm literally just trying to do everything I can to accommodate her and babies needs.
To top it all off she then sent me a message saying when I go over at the weekend to visit her and my parents can I save my wedding talk for when I am at my parents house as it bores her 5 year old son! 
I have literally mentioned my wedding once in front of my nephew when I told him he is page boy and that he will be arriving in a camper van which I may add he was SUPER EXCITED about.
I now feel like I am walking on egg shells about my wedding and my sister but it is a year away now and I feel like I need to get some things in place and sorted sooner rather than later before they get booked up. I literally feel like I can't ask her for measurements / transport questions / seating plan arrangements. Again I'm going to try to accommodate her and tell her she is free to sit at either the top table (as originally planned) or with her new partner and two children on the main floor, I honestly don't know why I care so much about it all as come to think of it at her first wedding I was sat on my own with a table of her friends that I didn't know! The rest of my family were either on top table or on another table. I also can't demote her from MOH as that will cause MASSIVE repercussions in my whole family.
Sorry for the rant I just didn't think this is how it would be, I honestly had it in my head that planning a wedding would mean my sister and family were as excited as me 
