“Give 'em an inch and they’ll take a mile.”
I like using a food analogy for contraception too, only mine is, “Using contraception is like eating food and then throwing it up, and pretending that is caring about your health.” It’s not healthy, it’s bulimia. Using contraception is the deliberate attempt to thwart the healthy functioning of the reproductive organs.
Here’s the thing - most of the time, thanks to God’s design, sex will NOT result in pregnancy. A woman recognizing her own fertility signals can use that information to either achieve or avoid pregnancy without tampering with how her body functions or how sex works (that’s the sin with contraception).
Nobody, absolutely nobody, in line with Church teaching says that every time you have sex you have to intend to have a baby. What we do say is that the reproductive organs serve a purpose and to thwart that purpose is wrong (whether that’s changing sex to avoid having a baby, or circumventing the process to create a baby in a lab).
My husband and I have a happy married life. We have two kids, but believe me, we’ve had sex WAY more than two times.
Also - to extend your analogy, sometimes it just so happens that a person really, really, really just cannot have dessert (or other food). It’s not cruel for a doctor to tell a person, “I’m sorry, if you want to live you have to keep a very close watch on your blood sugar, or salt intake,” or something else. There are people who maintain celibacy by choice, and if they are married that’s an enormous cross. There are also people for whom the act of sex itself is dangerous - NOT just pregnancy. But that’s also just life. I don’t mean to diminish their suffering by saying so, but suffering is part of life. To pretend it doesn’t have to be is unrealistic. (It’s also been brought up on this thread that contraception fails. A lot. I know more than a few women with pill babies. Vasectomies and tubal ligations fail. IUDs fail. Condoms break. Should a person with a major health condition trust their life to these, or should they abstain? Abstinence works. Contraception doesn’t have that guarantee.