I think having the in-home caregiver is more for my benefit than my husband. He has FTD, but resents the fact that someone has to babysit him.

Tell him, as said, the aide is for you.

It's crazy how the worst parts of our personalities are brought out with dementia in the majority of people. It doesn't matter what your husband recognizes the need for at this point because it's not about him anymore it's about you and what you need. Of course you can't explain that to him since he has FTD. I would also start making plans now to place him in a facility (well before you reach the extreme burn out stage or he becomes increasingly violent or hard to control).

So tell him the helper is for you, and leave the house when the caregiver arrives. He’s lost the ability to reason and make sound decisions so he can no longer drive the choices you make. You need this help, and the need will only increase. Make no apology for it. If the helper is experienced he/she will be well versed in how to handle a situation like this, rely on that expertise.