At first I thought of wiseguy comments like "I do go out OFTEN and proclaim the death of the Lord. I do it more often than we commemorate the memorial of Christ's death which were were told to do OFTEN so...perhaps you could consider me as someone who goes out VERY OFTEN...more than once a year..." Or you could say "He gave some as apostles, some as evangelizers...notice it says SOME and I am not one of the some but I am the less comely part of the body of Christ so just accept me as I am..."
In all seriousness, your wife needs to know you don't enjoy field ministry. Most would admit that they don't enjoy going door-to-door but they are compelled to do so. She might be mad or upset and worry about your future but perhaps the words written above could help her to reason that although you are not doing what everyone expects of you it doesn't make you a bad person. Bethelites don't put in pioneer hours from door-to-door but they are not slighted for that. They do something else for the Lord and they are appreciated for that. You could be mastering the fruitage of the spirit and that is your chosen calling and that should be accepted with equal merit. Just don't do it...you don't have to be rude or condescending but just decide what you will and won't do and be firm about it.