[HairOfTheDog]

Willful exclusion of children is grounds for an anullment.... You or your spouse married intending, either explicitly or implicitly, to deny the other's right to sexual acts open to procreation.

I am not Catholic or bound to Catholic custom, but your example is of a couple who are not of the same mind, not those couples who mutually agree.

[Aquinasfan]

but your example is of a couple who are not of the same mind, not those couples who mutually agree.

8-) That would just make the marriage doubly anullable. Usually one party is bringing the annulment. I've never heard of two people petitioning at the same time.