AIBU - Friend borrowing car

At present we have a 'spare' car. We are friendly with a couple who had two cars but chose to get rid of one of them. This was OK until the H started working shifts and weekends.

Since then the wife has been asking to borrow our spare car on a regular basis - to go shopping, to go to the doctors etc.

She always asks my husband if she can borrow it as he is soft and never says no

I probably would also be too soft to say no if she asked me.

However, I am finding it a bit annoying that we are, in effect, providing her with a free car whilst we pay road tax and insurance.

Her husband is adamant that they are not getting another car.

I don't want to fall out with them as they are good friends and we have helped one another out in the past.

However, this has been going on for a couple of months now and I think she is being a bit cheeky.

How do I handle this without falling out with her.