And, this really only becomes an issue if one person in the partnership actually wants to have more sex , but is conceding to their less-inclined partner, Brateman says. "Sometimes people want to be with somebody so badly that they’ll accept whatever terms," she says. "But then they come into their own, and [think], This is important to me. I do have those feelings and urges." Of course, this can cause a lot of stress and emotional turmoil for the person wondering why their partner doesn't want to have sex. Over time, resentment can build, and the hornier partner might feel like they're being rejected, she says. The only way to be at ease is to actually communicate about the situation.