I have no idea, I've never done it? Can I roll it over into DH's fund if his are lower? Or should I keep it separate?
You usually can roll over to any fund you want so if you want to roll it over to his, contact them to establish your own account. The fund you want to join should provide you with a form to complete & sign and they take it from there. It would probably be a good idea to look around at a few different ones first though to see if he's getting a good deal.