You may not have been asking the question re him using you, but on MN it will get answered for you, simply because so many young women get lured into a skivvy/aupair dynamic with men that are lazy arses that have little interest in the day to day grind of even 50/50 childcare.
The look around and quickly hook up with a woman they see as a good recruit.
Preferably young, solvent, working FT, who will relieve them of the tedium of childcare.
We see this regularly.
They often have a child with these men and it is only THEN the penny drops to exactly the sort of man they are with.
Take your time.
Look carefully at the state of his home and how good he is with his children, how well he cares for them.
Do NOT rush to step in to doing wimmin/wifey work.
Hold back and watch him get on with it.
If you take your time you will give yourself the space and time to make a well thought out decision.
Don't be rushed, it is invariably never in your best interests.