If you are going to seek fulfilment for parts of you outside of your marriage, it is important to have your wife's consent first. It may be a very difficult series of conversations, but being open and honest with her truly is the best way. I know its easy to get swept up in all this, it all comes from the core of our beings, but fall for it and step away for a moment before you decide to dive off a cliff into the water, so to speak.
As far as finding Mommies out there, that's a lot harder to do, and I honestly would not know where to point you.