No if you buy a second property and rent the first one out. The first one will probably need a new buy to let mortgage.
The property you rent out needs a buy to let mortgage, probably (you would need to speak to your mortgage provider and I am not sure you will get one in your own name) Not the one you live in.
To buy a second property, because you already have a mortgage that you are liable for, you will probably need a bigger deposit because only your partner earns income.
If your tenants move out, and it takes a while to get a new tenant, you need to be able to cover both mortgages.
Because you arent working, you will be classed as a dependent.
So they want to know your partner can afford living costs for all of you plus the mortgage on the rental plus the mortgage on the house you live in.
Which, unless he is a high earner is a big risk. They risk can be reduced by putting down a larger deposit. Until the 2nd mortgage is at a level where he can pay for everything.
It could be that a joint mortgage (because you already have one) will be difficult to get. But I would not recommended you putting in lots if the deposit and putting it, in his name only.
Theres also stamp duty to pay, because it's a second property, I believe.