As far as I know, no medical issues. I have told him to go to the GP but he says there's nothing wrong with being tired. Otherwise fit and healthy, not an issue at work, etc etc.
So an underlying medical condition aside, bit of back story - I work in the emergency services which includes a lot of night shifts etc. DP works 9-5 on a good day and today had a half day booked as he was playing golf in the morning.
Gets home at 5, we've both finally got an evening together after I had a set of four night shifts and have basically been ships in the night. I go and look what to make for dinner, come back and shock horror he's snoring on the sofa yet again.
He says it's because he doesn't sleep well at night.....well, yes, because he's constantly having a 3 hour 'nap' before going to bed! 
I just don't know what to do. I've come up to bed on my own, another evening written off. Just feel lonely.
Any advice or experiences would be so appreciated. 