Mia, his name is on the mortgage so by law he has to pay it. I have checked with my solicitor and I'm in the UK, so go and see a solicitor and have him paying his share.
Just wondering:are you afraid that if you take him to court for no mortgage payments, you feel that there will be no possible R? I was afraid like you that if I was going for legal separation it'll mean no chance of R, unfortunately I know there is no chance for me so I'm looking after my kids and me. You need to do the same as at the moment your H is MIA!