I listed one of many beliefs of the faith, whereas you claimed to boil the entire faith down to a single phrase—I'm having trouble understanding the supposed contradiction.

There isn't any contradiction, per se, its just that observing that Catholicism says something about holy orders or marriage doesn't actually say anything about what Catholicism also says about relations outside of these sacraments, which is the question at hand here.

While it certainly is a gross summary, saying that Catholicism calls on people to sacrifice (everything, if necessary) for any person, is accurate and pertinent to the idea that it only suggests this for one's spouse. Being willing to sacrifice for your spouse is necessary but not sufficient to be an optimal catholic.