Married but not married, please someone relate?

We did not have the best relationship in the beginning of us. It started out insanely well, too well. We have everything in common and the things we don’t, we still like to share with each other. My insecurities got the best of me, and my Immaturity got the best of me, (we had many fights, where I got way out of control with my emotions) we had a 5 year age difference, I was 18 and he was 23. Fast forward, we have been together for almost 5 years, lived together for almost 2 years. My mom just moved in with us because she couldn’t afford to live in LA anymore. Now his family, dad mom and sister are going to move in with us for the same reason. When talking about marriage previously, he said we will. Not soon but somewhere in the future. Because of my mental problems, my emotions run a marathon every time I try to discuss my feelings, and I end up saying horrible things. So having the discussion AGAIN would be way too much. But seriously? I cannot continue to be married without being married anymore and I don’t know what to do!!! He even said that if his parents can’t find jobs here, they will leave his 16 year old sister with us. So wait?! We’re not even engaged and I have to mother your so sister while living with my mother?!?! Insanity. This is making me super upset all the time. I feel like I’m in a rut, and dreading next month that his family is coming. I need advice or someone that can relate and help me through. And before you ladies say I need to break up with him, I can’t because this man is the most perfect man I couldn’t even dream of. Thank you