Sophie- Like I said, I am no expert...it is possible that it could be a MLC. Was there some event that could have started a crisis?...lose of job, a serious illness or loss of a loved one?
Do you have any kids? It sounds like your H is still at home...so it can be very difficult on you. You need to detach, GAL and take your focus off your H.
MLC can take years so it is possible that your H is MLC...Keep reading and posting. Hopefully you will get some of the more experienced DBer's chiming in.