Need some advice

I have been with my SO for 9years and still no proposal, i suffered a misscarriage last year which he never came to the hospital! I suffer with POS and endromesious(spelt wrong) and its been a year since we been trying!

 But i have been thinking about leaving him for along time now, hes aggressive and has been violent in the past, its new years eve and i have no money due to him not working so i pay all the bills and all the household expenses as well as caring for our 7yr old son who i pay childcare fees on top off as he refuses to pick him up from school

Anyway back to the point, its new years eve and its his cousins birthday and due to me having no money, i cant go out this year but he has said its his cousins birthday so hes planning on going out although i only know this because i heard him on the phone, my son has gone to his aunties house so i will be bringing in the new year on my own! And i cant go to my family as i moved out the city to be with my SO 8yrs ago and feeling like ive made the biggest mistake of my life!

Should i be upset that hes still going out? Or am i over reacting?