So, how are you explaining these expenditures to your wife? Is it stamps? Entertainment? Something else?
You are what we call in America a sugar daddy.
If you want to be a source of income for this woman (for that's what you are), then be sure to budget for that and I really hope you'll at least tell your wife that money is flying out the door and over the border. Maybe tell your kids that, too, if they want or need anything and you can't afford it because you're too busy paying a prostitute.
Maybe she has some feelings for you. I don't know. But this is an awfully convenient setup for her. She gets money from you without having to do you.
If you want to see if she actually cares, try cutting off the money supply and see what happens.