[quote="flyingfish, post:7, topic:183864"]
I've never seen anything in Catholic teaching to suggest this. Married couples are only required to be open to life. It is possible to be open to life while intending to contracept, since the majority of people who use contraception end up having children.
The OP's girlfriend can't have children because she'd die from a heart attack, but she is still open to life if she intends to have children should the just reasons for not having them go away.
I think if you are right, then something like 98% of Catholics are in invalid marriages, because something like 98% of Catholics use artificial contraception, and very likely intended to when they got married.
I've never heard of an annulment being granted simply because a spouse intended to use contraception (i.e. they were open to children, but instead of NFP were going to use condoms or the pill or whatever). It seems like annulments would be extremely easy to get if what you say is true.
Actually, contraception is a relatively frequent ground of nullity. Chances only are that some postponement would not invalidate even with the use of contraception, but that's a new thing in ecclesiastic jurisprudence. What is more, a decision by one spouse without input from the other to have no children or only one or not until they make six digits or something, would also invalidate. "Opennness" is not some abstract attitude that in theory one has no problem with it, nor can the right to have offspring be conveyed under a future condition (any essential part of marriage being conferred under a future condition makes marriage invalid). It does not extend to "openness to openness". This openness is well illustrated in case of infertile people who do all that would normally be done and would be accepting of children but despite all they do, they can't conceive. This is different from making a choice not to conceive. This said, I can't say with certainty that the marriage would be found invalid, but I would have doubts as to its validity.
What 1ke said reflects on a traditional distinction between intent not to fulfil and intent not to obligate oneself (respectively *animus nonadimplendi *and *animus non se obligandi *for the nerds among us). Without mutually exchanging each other's procreative power (which basically precludes unilaterally making binding decisions), marriage would indeed be invalid. Exchanging it, but not intending to use it would be a different thing, generally not invalidating. If the parties' attitudes were such that they would either not confer or not accept the rights themselves, then marriage would be invalid. This does not mean that the marriage in the OP's situation would be invalid, but, respectfully, it means there's a lot of problems with certain positions with regard to it.
[quote="flyingfish, post:10, topic:183864"]
When you said that it's wrong to enter a marriage where one person intends to use contraception, I assumed you meant such a marriage would be invalid.
If that person intends 1) to keep using it indefinitely in order to prevent any pregnancy from occurring or to reserve the right to do so, 2) to decide about #1 unilaterally, then the marriage is invalid. I've never seen a canon law case or doctrinal work dealing with the case of compelling health reasons from the very start of marriage and intent being based on it, so I don't know if perhaps that marriage wouldn't escape invalidity (marriages, once contracted, are presumed valid), but in a typical situation, it invalidates. It would at any rate necessarily be invalid if a person contracting withheld the right to decide on the offspring (essentially contradicting the vows being taken).
Would you mind giving a source for Church teaching that states a faithful Catholic should not marry a spouse who intends to use contraception?
You can't have a source on every little detail in our lives. However, there's a source that we shouldn't have sex with anyone not a spouse and in an invalid marriage, the other person is not a spouse.
The Church allows Catholics to marry non-Catholics for instance. Non-Catholic very likely use birth control (with perhaps a few exceptions).
Non-Catholics are not guaranteed to intend to exclude indissolubility or offspring, which is a stance held by the Roman Rota as well, despite what lower tribunals tend to say. Disparity of faith (or cult) is an old impediment and it isn't a defect of consent (i.e. whatever affects the content of the consent). It deals with the fact that being married to a non-Catholic or especially non-Christian could be dangerous to one's faith. The Church doesn't really "allow it", she actually prohibts it with the possibility of dispensation.
In all my readings of Catholic/non-Catholic marriage I've never seen it taught that a Catholic may only marry a non-Catholic if the non-Catholic agrees to use NFP, or that it would be somehow immoral to marry a non-Catholic who intends to use birth control.
There's a limited level of detail of instruction that will be affirmatively given to you without your asking and without the responder having a reason to contemplate the issue you didn't ask about. The requirement (for validity) to be open to children is not waived for non-Catholics.