Jesus.....well, your present arrangement is mutually beneficial.
He's apparently up front about his plans and you are better off than you were....for a long time.
The problem is obviously...the future. What are you going to do when this arrangment goes away? What can you do to prepare? Have you any marketable skills so you could support yourself?
I hope your not thinking you'll still be welcome when the wife arrives. That's not likely for very long.
I hope you get it together for a happily ever after. Good luck.