My gut reaction is she is trying to hurt you. Maybe you can send her pics of larger breasts and say how you wish hers was bigger or if she has large breasts send pics of small breasts and say you wish her's were smaller and perkier. She can't do much about her breasts just like you can't do much about your penis size. You can claim you were playing her game and you thought it was all in good fun if she gets mad at you.
Hell I love all cocks no matter size shape girth length color or age. Size doesn't matter. They all get the job done. Some are easier to use than others for certain positions or openings. It is easier to take a smaller penis orally or up the ass for example. To be double penetrated up the ass and pussy it is easier with longer penises.
Talk to your wife ask her what her needs and desires are. Maybe she is interested in meeting other partners and getting into the swinging lifestyle. That doesn't mean she loves you any less. I love being a true slutwife in every way but I only love my husband. He enjoys it as much as I do. It is just sex and usually we are together only fucking others.
I hope this was helpful. Turn it into a positive and don't let it get you down.