My family are, largely grown up.
^Are you talking extended family who fancy a holiday at your expense?
I'd go with 'no, not this year, I'm exhausted'.^
Once you have rested, control the flow by deciding how often and when you wish to host and inviting your preferred guests (going to B list If they cant come and you want to make another invite) and being too exhausted otherwise. Or maybe in addition to those you want to host, you could bear 2 sets of presumers annually, if they invite themselves far enough in advance. No one but you and your dp needs to know what is your restriction on numbers of times you are willing to host, or how late is too late to ask.
Next year, either risk creating an unavoidable tradition for the invitees by inviting them a second year in a row, or very purposefully mix it up, telling the first set of invitees 'maybe next year'.
Since yours are largely grown up, soon enough they might be usung up all your hosting energy bringing oartners and then grandchildren too. This will make it way easier to not have room for anyone else except the few you want to invite.