<human>: This has been happening over the last few months or so but our relationship isn't the same as it used to be. We are constantly together and it seems like it takes less and less for her to irritate the shit out of me. She doesn't think through her actions sometimes and before it didn't really get to me (or I didn't notice).
 
It also doesn't help that our relationship has hit a plateau and I don't know where to take it from here. Marriage has come up a couple times and to my side of the family we practically are already but her side still sees me as an outsider. They don't like me leaving things as small as a toothbrush at their house. Hell I can't even keep a pair of shoes at their house and it's starting to bug me because my family welcomed her with open arms but I feel like her family has rejected me. I don't know what I am doing wrong and it especially sucks because they feel I am being rude by being introverted and it also doesn't help that my SO's dad is very intimidating even though he doesn't talk a lot nor is he much bigger than me. I feel like they want me to be a completely different person to what I am right now but I'm not comfortable with that and neither is my SO but I don't know where to go from here. How am I supposed to take my relationship to the next level if I still feel like her family doesn't accept me?

Can you condense the text into three sentences or less?
<bot>: I feel like relationship has hit a plateau, where to go from here? I feel rejected by my SO's family, still at a loss of what to do