My wife and I are at opposite ends of the religious spectrum. I have tried to become more observant and she is happy to remain less observant. She will not rid the house of Chametz and may even eat it, while I will refrain from Chametz. Given the consequences of possessing and benefiting from Chametz, what are the Halachic and Ruchani consequences to me? Can I avoid taking a vow I can’t keep if I nullify and sell my Chametz if I have in mind to do so on my behalf only? What is your comprehensive advice?

Your situation sounds complicated and I suggest you try to get some more comprehensive advice than I can give here, since your situation impacts on all aspects of life, and, since I can only assume you love your wife and are serious about your devotion to Judaism, you will have to make a lot of choices and compromises, hopefully being able to both maintain and express your love, as well as minimizing and deviation from Torah law. As regards to Chametz, a Jew is not allowed to have Chametz which is owned by another Jew in his property. If your wife wants to have Chametz on Pesach you should deed her the ownership of a room in the house, even the kitchen, and ask her to keep all her Chametz in her own room. Then you can say the "Bitul Chametz" in which you relinquish care and ownership of all the Chametz you own, or sell the Chametz you put away until after the holiday. On the holiday you will have to treet that room as if it is not yours and going in is trespassing.This arrangement is neither simple, nor is it halachically foolproof. It will however take care of the Torah prohibitions, and indicate to your wife the degree of your commitment without asking her to give up her life style. Deeding the room has halachic ramifications, and you should try to get a more local Rabbi to help you with that one. I wish you much success.