Help marriage difficulties?

I am on my 2nd marriage. It has been a very difficult marriage. I have 2 children from my previous marriage and my husband has 3 children from his previous marriage. We also have a daughter together. We lived together for 4 years and it was too difficult. We have lived apart for 4 years but tried to perserve with the marriage. My children do not get a long with his grown up children. His grown up children will not stand on their own two feet and keep coming back home. The livein situation is not workable. We would need a 6 bedroom house to keep the family with 2 living areas. It is a matter of money. My husband does not want to go without and is resentful towards supporting my children and me. I work part-time but I do not earn a huge amount of money. The marriage has come to a crunch. He does not trust me and making accussations that I am seeing someone else. Which I am not. He is also trying to control what I do. He is allowed to do what he wants. he never admits that he is sorry.