Okay, so going based off what you said, NFP would be an appropriate option available for married couples? (I've seen Catholic-sponsored videos promoting NFP, so I'm guessing that it must be somewhat agree upon)
It's the only option frankly and if that doesn't work for a couple because of biological factors (like the woman can not be charted, etc) then the couple is pretty much screwed, excuse the pun. Here is where the rubber meets the road, excuse the pun again. Some will say that is where it's pastoral, you go to your priest and he tells you what to do and handles it on a one on one basis but the reality is, in Catholicism we do not have this concept of "economia".
In Catholic moral theology there is just no wiggle room for this. It's total abstinence or you keep having children. Now there are some lope holes, like "for the good of marriage" where if you are married to a person who refuses to do NFP and keeps using contraceptives, you aren't obligated to refuse them sex if that can lead to divorce. It's their sin, not yours. This is where the attitude of being open to life comes into play. Like I said, it's a two fold thing. Even if the other spouse takes birth control pills or wears a condom, it's them doing it, not you. You are open to life but they aren't so you are okay but you can't just kick back and enjoy the "get out of jail free card". You have to be worried about your spouse endangered soul because at this point, they are probably going to hell so you pray for the spouse and gently try to get them to convert over time.
Now, where it really gets screwed up, you can go into any random parish in the country (U.S.A.) and you may hear the truth... or not. There are a lot of priests out there who will tell you, you do not have to be open to life if you can't. They will tell you to use even artificial birth control pill, despite the fact that they can act as an abortifant . There are very few who will tell you that even if you are one of those woman who are high risk of losing their life, they will tell you the only option is abstinence. No, you can not be sterilized.
Now, here is where it really gets screwed up even more... lets say your husband has had vasectomy years ago and now he sees the light. Has this big conversion experience and wants to live the Catholic life down to the last letter, to a "T". Well, he has been fixed, a major no-no to Catholic married couples. It's a sin to have deliberately done surgical sterilized sex. So what's a newly converted, seeing the light Catholic husband to do? he can have that vasectomy reversed, if he's seen the light and all... but he does not have to... All he has to do is repent, be really sorry he is fixed, confess the vasectomy and he can have all the sex he wants. But the coupe who always seen the light, they have to abstain for the rest of their young lives. So that is where a lot of devoted Catholics struggle with this big time. The rules doesn't seen to apply evenly. Some are off the hook while others are held to the highest of standards. So we do have a sense of "econemia" after all but what we can not do in any uncertain terms is get surgery or use any kinds of ABC, so you know what? You figure it out because I can't.
