The consummation of the marriage of fallen angels to human women produced the race of the Nephilim (Genesis 6:1-4).  Jesus said that angels neither marry nor are given in marriage (Mark 12:25).  However, the two hundred sought wives and from them children (The Book of Enoch 6:2).  God made everything, and He gave it its order (Catechism of the Catholic Church, Second Edition, #292).  Unnatural relationships lead to sin and destruction (Genesis 19:4-13).  Unfortunately, these spirits chose to cross a boundary (Jude 1:6).  Whether they belong to angels or humans, dreams of behavior outside of God’s will are never good (Catechism of the Catholic Church, Second Edition, #312).  Our conscience helps us to freely navigate the God-given boundaries with care (Catechism of the Catholic Church, Second Edition, #323).  Otherwise, we set ourselves against his will and design (Jude 1:7-8).