I have two sub-plots that my main character has minor involvement in. They are centered on her boss, a major character, and other minor characters. One sub-plot results in my main character discovering her husband is cheating on her, so I think it fits. She has little involvement in the other sub-plot, but it gives a deeper view of her boss, who is a major character throughout the story. Do sub-plots need to involve the main character more, or does a sub-plot that enhances the character of a related major character work? I have a lot of sub-plot ideas, but many focus on other major characters, and don't involve my main character, at least not directly. I'm concerned with going off on a tangent.