Additional Info: I thought getting married and having a child would make my husband more responsible. We even moved from the city to a Boston Metrowest suburb, but he still goes out several nights a week with friends and comes back intoxicated. Recently he was too hungover the next day to go to work, and missed a big client meeting and now his job is at risk.
His immaturity will likely affect the negotiations of a settlement. I find that an immature party is sometime very unreasonable in his/her demands and expectations. You did not mention whether you have children. If you have children, his behavior can (and should) be considered when making an order for custody and a schedule for the parenting plan. It will likely not, however, make a difference with the equitable division of the marital estate (unless you can show he really spent down substantial marital money with his partying).