Announcing second baby to difficult family

J

To save a long, irritating story, my sister in law has always been in competition with me. Im not sure why, but I am exhausted at the fact of trying to mend or even have a decent relationship with her. I honeslty think it has to do with stability. Shes now 30, im 24 and we are just at very different stages in life.

Her brother and I met in High School, dated for 8 years and got married on our anniversary date, which happened to be a month before her wedding. We didnt tell her as I didn't want to take her "shine", (we had a private ceremony, just us 2) and i was even her makeup artist and hairstylist for her wedding - for free and even did all three of her trials for free. Anyways, she ended up finding out that we got married "first" AFTER her wedding and basically hated me since then and even stopped talking to her brother for awhile. I told her our reasoning for not telling her about us getting married and in order to let her have her moment and all she told me was that it was "my fault" and that it was a "personal problem" that I didn't have the wedding I really wanted. so she basically just disregarded me and the fact that i was looking out for her best interest since then. this was in 2015.

We then got pregnant the following year, 2016, and she hasnt made much of an effort to be in her nephew's life nor make an effort to mend our relationship despite me reaching out to her multiple times. Even at our baby shower she's sulked in the corner and didn't participate at all and even left early.

Fastforwarding, she recently bought her "forever home" with her husband and is now miraculously coming around, wanting to be nice to me and see our son. Of course, I welcome her newfound kindness but we are now expecting our second child, and I feel things are going to backtrack.

Our son is 10 months old, and we will be having our 12 week scan this Thursday. We will also be visiting her with family this weekend. Should I tell her privately? Or keep it to ourselves? Im a very small woman and being that this is my second pregnancy, its getting hard to conceal. Im just tired of her drama and I don't like the fact that she takes her insecurities out on me. Any advice on how I should approach this situation?? Also her husband and I have a great relationship and he has never been mean to me despite all this drama so my issue really is only with her. Its a mess!