There are websites that will help with finding a roommate. Co-abode is one and there are otheres.
Caution on the idea is your ex does not like this idea. I was told that mine could ask for the kids full time if I did this.

Good move!...You will receive some rental income. Read up on being a landlord and ask for 50% security deposit up front. Have the tenant sign a tenant agreement and lay down the rules (ie. noise after 11pm, parking, smoking, partying, etc...)

Then, ask your friends for referrals...sometimes they know people who would need a suite.

If it gets too much for you, hire a property management outfit to interview but you would pay them a fee....but it is worry free because they do all the screening...(and the evictions too!)

Sometimes, if you are lucky you will get a tenant who will also become your friend.