Pressured to marry, but not at all prepared for the sacrifices and concessions and extra care it takes to live together long-term. Your partner is not being respectful of your needs and its not going to get better without intervention.

When things have settled after new year's sit him down for a serious conversation and explain that this lifestyle isn't working for you. Your sensory issues are part of who you are, and you shouldn't be expected to isolate yourself in a room while he hosts loud parties. If he can't see things from your perspective then start taking steps to seperate. Put yourself before anyone else.