Need to Vent but also need some advice!!

YuMMMy721

So my FI's 20 year old sister and her 10 month old son have been living with us for the past two months (long and complicated  story, basically she mooches off of anyone she can, lives off the government, has no job, and is lazy as can be!!) During that two months my FI became my FI which was all good! But now I'm trying to plan my wedding and this 20 year old punk suddenly thinks she gets to be a part of every conversation him and I are having and help make every decision?!? YEA RIGHT!! I can't really even stand the girl she definitely isn't planning my wedding!! And on top of that I can't even have a conversation with my FI in MY OWN HOUSE about the wedding because she listens to EVERY conversation we have and then it gets back to my FMIL (whom I also don't have the greatest relationship with, goes back to the girl living with us, my FMIL lives just 2 miles down the road and wont let her daughter live with her, but its fine for her to mooch off of us!!!) Frustrating situation, but I feel like I am hiding in order to plan my wedding! My question/advice needed is it rude to ask her to leave for a few hours at night some nights for us to be able to discuss our wedding?!?! I'm blowing my budget eating out dinner several nights a week just so I can talk about my wedding! God we even set at Pizza hut for 3.5 hours one night to do our homework for our church marriage counseling sessions because we couldn't discuss in front of her at our house!!! So frustrated!!! Hope everyone out there in Knot land is having a better day/month!!