"Grace is demonstrated through the covenant of marriage; the covenant between God and mankind and the covenant between the two human beings. Such a covenant can exist where there has not been a ceremony through the couple's promise of commitment (whether spoken or not) and the couple's sexual union." Hmm... wonder whether that is too protty as well.

Since I pretty much agree with this, it is probably pretty protty. Apologives for the plosive alliteration.

Limiting the ability of God's grace to be present in a relationship because that relationship has not been constituted/acknowledged in a liturgical setting is theologically problematic, and some might say uncatholic. However, it's also difficult not to feel that a statement of commitment is crucial to the creation of a relationship which is covenantal on the model of God/Israel and Christ/humanity. There was a hugely public acknowledgement of self-giving vulnerability in both those cases, and I think that marriage does demand a similar action.