As-salamu alaykum sister,
First of all, at 28 you are still young. If I understand you correctly, you are separated and not divorced. As it has been two years and you still are not divorced, I kindly suggest you seek out legal assistance to get the divorce done yourself. You can’t marry until you are divorced. That is the first thing. Secondly, look at your situation as a temporary one (your sister in laws using your furniture, etc.) because it is. You will move on with your life, have your belongings back insha’Allah and have a live which makes you happy. Often times we go through tests and trials to make us stronger. Look at this period in your life as one of those times. Take this opportunity to begin to put your life back together the way you want it. Continue to help out at home, but tell your brothers you will be contributing less as you need to save for your future and they need to help your parents as well, as it is prescribed by Allah SWT.
Sister, you will never know who Allah has for you until you are divorced. Once you are divorced, insha’Allah, Allah will bless you with a wonderful husband. Allah cannot bring you a good Muslim brother while you are still married to another can He? So please, get your divorce insha’Allah and make dua to Allah that He brings you who He has for you. You may be very happy with the result! However, you must take the first steps by becoming a single woman again in order for his to happen. Regarding marrying the man who is married and wants children, I encourage you to wait until you are divorced and everything is settled before you decide to commit. Think about this very carefully as you are currently in a situation in which you want to get out of, and you feel no one will be available to marry you. Please do insha’Allah wait. After your divorce is finalized and things are settled, you may not see things the same way. Please be patient, Allah knows best.
You are in our prayers sister, please let us know how you are.