"Heterosexual sex" refers to sexual activity between a man and a woman. It describes the physical intimacy of two individuals of opposite sexes. Full definition
There is a commonly - accepted narrative when it comes to casual heterosexual sex and the women who participate in it — that, afterwards, they almost always regret it. (businessinsider.com)
A gay man can marry a woman and perform heterosexual sex acts with her, yet still be gay. (nakedpastor.com)
There is no differentiation between heterosexual sex and homosexual sex. (religion.blogs.cnn.com)