Thanks for the responses, I've been avoiding this thread all day because the reality is that I don't want to believe he's lost interest.
We have had a couple of issues this past few months. He's SAHD, I work full time, there were a couple of issues surrounding our roles and finances, but we discussed that and actually agreed on a resolution. (there was a thread if anyone is interested in the back story)
It did occur to me that he was depressed, when I brought that up it did not go down well - I'm all out of ideas really. I continue to suggest things for him to do on his own, like go away for the weekend to spend time with friends, meet friends in pub, join a local music group - even suggested him getting a job in a music venue (as was suggested on a previous thread).
When we do talk, we continue to make plans together, i.e next Christmas, summer holidays - often this is over a nice cup of coffee in our favourite rural pub - at home though, he just disappears inside himself and I cannot get in.
He's not possessive at all with phones or laptop, he leaves his emails etc open - I don't read them but they are on the screen if I'm passing. He's just quiet and very irritable.
I feel like the delivery person, the person who brings home the shopping, the person who pays for things and the person who just happens to live there 
The thing is, I want to be there, I could get my own place (it would be difficult) I have supportive employers/colleagues, and I have confidence that I could arrange suitable childcare while I worked etc but I don't need to do that because I'm (I was) happy where I am.
He, on the other hand, may well be stuck in a rut, and can't leave even if he wanted to - that's the worse thing, he could be staying with me, sleeping in our bed and living in our home just because he has no other option...