What it means when a man gets sick to his stomach after ejaculating in a woman?

Anything or nothing: The possibilities are endless. Probably they have little or nothing to do with you. Don't take it personally. He could just have eaten or drunk something bad, have a flu or virus, etc., be nervous or have sexual anxiety or guilt feelings and on and on. Try to talk about it if you care for each other. It may become part of your personal love history as you go through the years. Or, you may move on.