I appreciate the thoughtful response, Henri. I share your skepticism about a deity and afterlife (though I don’t claim to know enough to know that there is nothing at all).
I have a similar answer about purpose in my head as you lay out here. My purpose has to do with the here and now, with serving my family and friends in this life — and with serving others who read my work.
But I would still classify all of that as a leap of faith. After all, in your case, your wife is not you. She is a separate person, who is not subject to your will, and can do what she wants. She could hurt you, betray you, or simply decide that she doesn’t love you at some point. Thus, you are putting faith both in her and in the relationship you have. You’re willing to put everything into serving that relationship (as is she, I’m guessing).
In a sense, it’s like a game of cards, where you’re each telling each other what you have in your hand, but you can’t show each other. You have to simply take each other’s words for it. That’s a simple form of faith — but one we practice every day.