I am on SSD. I have been legally separated from my husband since 2010. we were only together seven months. Can he take my survivor benefits?

If you are divorced then no he would not be entitled to any survivor benefits. If you are still married then I think he could still get them, unless you have a Separate Maintenance Agreement (there is no such thing as "legal separation" in MI)  that says he is not entitled to them in the event of your death.  This response is general in nature and is not legal advice.  No attorney client relationship is formed by it.  Good luck to you.