From On Colossians, Homily 12. Translated by the Rev. J. Ashworth, 1879, and adapted by me.
“And how do they become one flesh?
“As if you were to take away the purest part of gold, and mingle it with other gold, so here also. They are melted together (as it were) by pleasure; the woman receiving the most prolific part, she nourishes and cherishes it, and contributing her own share, she returns it, a Human.
“And the child is a sort of bridge, so that the three become one flesh, the child connecting each to the other on either side. For as two cities divided by a river become one if a bridge connects them, so it is in this case. And yet more — for the bridge in this case is formed of the substance of both, just as the body and head are one body. They are divided by the neck, but not more divided than connected, for lying between them, the neck brings each together with the other. And it is the same as if a chorus line comes into close rank, and extending hands, becomes one, for the joined hands do not admit of their being two….
“What then? When there is no child, will they not still be two, then?
“No, it is plain that their coming together… diffuses and commingles the bodies of both. And as one who has poured myrrh into olive oil [to make chrism] has made them one, so in truth is it here, also.
“,,, Shall I tell how marriage is also a mystery of the Church?
“As Christ came to the Church; as she was made out of Him, and He turned to her with a spiritual intercourse. For it is said, “I have espoused you to a husband, a chaste virgin.” (2 Cor. 11:2) And hear how he says that we are of Him — we are all of His members and “of His flesh.”
“Thinking on all these things, then, let us not throw shame upon so great a mystery. Marriage is a type of the Presence of Christ.…”
Here is a very nice explanation of the “unitive” and “procreative” purposes of marriage and sex.
Re: the identification of myrrh and chrism, it’s very strong over on the Eastern side of things, where they had more ready access to various rich ingredients. They even add all sorts of things, like rose oil, to the original recipe: “The Lord said to Moses, ‘Take the finest spices ‑‑ 12 pounds of liquid myrrh, 6 pounds of sweet‑smelling cinnamon, 6 pounds of sweet cane, and 12 pounds of cassia (all weighted according to official standard). Add one gallon of olive oil, and make a sacred anointing oil, mixed like perfume.'” (Exodus 30:22‑25)
Over with the Orthodox, there’s actually a chrism-making monopoly with the patriarchs of Constantinople, Moscow, Belgrade, and Bucharest. On the plus side, this helps maintain communion and allows use of a zillion crazy-expensive ingredients. On the minus side, that’s a pretty darned top-heavy distribution system.