A legal separation agreement can cover whatever issues you desire. For example, the separation agreement would likely contain language addressing the division of personal property, exclusive use and possession of the marital home and spousal support.
While you did not state this, it appears that you have a long-term marriage. As such, spousal support may certainly be an issue. As a general rule, support may need to be addressed where the marriage is at least ten years and there is a substantial disparity in the incomes.
As to insurance, this would likely remain the same during any separation. If you divorce, you would each need to handle your insurance separately. Until then, the current policy could likely stay in place.
As to his retirement account, you are entitled to one-half of anything that was accumulated during the marriage. For example, if he accumulated $50,000 during the marriage, you would be entitled to $25,000 once the proceeds were distributed.
Please let me know if anything requires clarification.
Also, several customers have asked how they may direct a question to me in particular. If you specifically want me to assist you in your legal matter, just put "FOR JOSEPH" in the subject line and I will gladly pick up the question as soon as I am on-line.