Here it goes. Sorry it may be a long one 
When my SIL found out i was pregnant (we have told everyone when i was 3 months) she wasn't happy as she thought she would be the first one to have a baby. She is younger than me by 7 years and she is with her former boyfriend around a year my partner and i are together for 4 years. We weren't really trying but thought if it happens then it happens.
The whole course of pregnancy not even once she asked how was i feeling or was i alright. Her BF asked few times and made an effort but she just ignored me most of the time and didn't bother with me. We all live together with PIL, BIL, SIL and her BF as its a big house.
I gave birth to a DS and he is 6 months old now and she thinks she has a right to him. The first picture ever of DS she posted online without asking me or my partner. I think as a parents we have a right to do it first if we wish to she did not ask if we mind or anything i was absolutely fuming!!!!
Shes one of them that "knows everything" about babies and how to care for them despite the fact she hasn’t got any and looking after someone else’s kids isn’t the same.
She calls him "my boy" "how is my boy?" or "where is my boy?" when she knows exactly we call him that and it really annoy me and i have told her that he is my boy not hers but she keeps calling him like that just out of spite.
When she has friends round she demands brining him for them to see him even tho we do not know them. She doesn't ask she actually demands and send text after text saying "Bring him so ZZX can see him" so we just ignore her but i have told my DP to sort her out as her behaviour frustrates me.
My DP works away so he only sees LO over the weekends and Friday if he manages to finish early. So Saturday and Sunday i would like to have a family time with LO na DP buuuut nooo Saturday morning or Sunday morning she comes to our room wanting to see DS.
She is an auntie and not a mother to my LO. When she holds him i feel like i cant get him back from her because she makes it just awkward and she passes him to everyone like a bloody parcel.
Its my first baby i know i may be overprotective but AIBU?
I understand she may be excited and whatever but to have a relationship with LO she has to have relationship with me and her DB but we just don’t get on because she is spiteful, two faced and just not a nice person.
Whyy would i let her see him when she did not bother about me when i was pregnant.
Sorry for a long post i think i needed to bent as well as my partner is sick of me complaining about her ahha