A valid marriage contract is a bit like a valid home insurance contract, by which the insurer agrees to protect you against potential household disasters.
1. You can say that the policy is perfectly valid before you ever exercise your right to claim on it. Equally, you can have a valid marriage before consummation or reproduction.
2. You can even intend to *never* invoke a claim on it (as adamantly as some never intend to have children).
3. However, you cannot say on the basis of 1 and 2, that the purpose of insurance is not intended for potential household losses. It is. It is also designed to regulate the insurer’s responsibilities, rather than mandate household losses. Marriage is, along with mutual fidelity, designed to regulate (rather than mandate) parenthood.
Something may be tolerated by law without the law making it legally intended by design. It is clear that coercion and non-consummation are legally tolerated (being voidable causes), but not legally intended.
A voidable marriage remains valid until one party is aggrieved enough to seek redress (and cannot be shown to have agreed to it). You can have a valid marriage, even though one or both partners consents to marriage under duress, or is deprived of conjugal rights. The law simply permits the aggrieved partner to cancel the marriage obligation with an annulment.
A valid marriage is invalidated though the petition of the aggrieved spouse. This is an accommodation of their personal privacy. The spouse must decide what they can tolerate, It does not mean that marriage is not geared towards this purpose. This does not mean that the institution of marriage can ever legally *intend* coercion or non-consummation.
Same-sex marriage legally intends non-consummation. It contradicts the purpose of marriage.
What is clear is that marriage allows society to channel the potential impact of heterosexual passion (including children) into stable committed responsibilities. Paul alludes to this in 1 Cor. 7:6 – 9, i.e. it is better to exercise that passion within a stable committed partnership (marry) than to burn.
Marriage law, by design and intent, accommodates the potential for children. The vows of marriage exchange mutual assurances that any potential children born of the wife will also be the husband’s parental responsibility: the automatic presumption of paternity.
Therefore, we must consider what the law, through marriage, intends to *regulate* (mutual fidelity and shared reproductive rights and responsibilities). Marriage is open to those couples who, the law considers, *at first sight*, have the constitutive (rather than tested) capacity for immediate lifelong fidelity requirement *and* potential reproductive responsibilities of marriage. This is why being already married, being of the same sex, being close family relations and being a minor completely invalidate a marriage.