How can I better perceive how I am heard by my wife?
Thank you for your question.
I think there's a few factors that would be helpful to know in accurately answering your questions. But, I will give it a shot and maybe ask you those questions as they may be helpful in determining how your message is received.
I would start by asking your wife specifically what is the message your expression or tone is portraying. I know you said she sees in the worst possible light - is it anger, sarcasm, criticism? Is it always the same. There's a lot of funny meme's and shirts that sort of hint at the same issue - "My face said what my mouth didn't..." But there are people who have to be truly conscious of what their face is doing. This can take some practice.
Another helpful hint is taking space before having a difficult conversation to sort out your thoughts and responses to what your wife is saying before you respond. If your initial response tends to be "unfiltered", it may help you to decide what to say and how to say it in a tone that may be better received. There also could be no issue with your tone or expression but it's something that she's particularly sensitive to.
Do you have similar communication issues with others? Do you have friends or family that you could ask - "Hey, when we are talking, am I making a certain kind of face or is my tone a certain way". Sometimes getting people to help you be more aware can also help you to practice different communication styles. I would hope that your wife would be open to answering the questions about what about your communication is bothersome to her, especially if you're sharing with her that you're working to improve things. Maybe she even has some suggestions on ways that she would like you to communicate that she feels she would be more receptive. If not, I would opt for trial and error. It's ok to say "That came out wrong. What I really meant to say was"....
I applaud your for having good insight that there is a communication issue and for being interested in rectifying it. Best Wishes.