Don't know for sure, but as with a lot of other things, if it's joint, there needs to be agreement between parties, and if you haven't agreed, then why should you go along with it - you have as much right what you want as he does. In other words, I'd say no.
He has to have your agreement to sell it, and if you are not happy with the price he has accepted then do not accept it. Do you really want to sell the house or is some pressure being put on you. I would see a solicitor first ... how are you going to split the proceeds, have you agreed on that ??
If the both of you are on the deeds, then you both need to be in agreement. A solicitor is IMPERATIVE in this sort of thing, especially where marital splits are concerned.