Hi Kitty, another one sided tinnitus person here, don’t want to say sufferer as over the years I have learned to accept my tinnitus as being part of me.
White noise can be found on YouTube free. Get your DH to use earphones, or just one if he sleeps on his side and the sound of the white noise should lull him to sleep. You can buy devices from the Deaf Association (they must have a more pc name for it now) which play a selection of sounds, my favourite was a steam train.
Should be packing for my hols, if anything else comes to mind I will pm you.