When, if ever, is there a heter for a married couple to use a condom as a form of birth control?
Question was inspired by this article
It is by far one of the least-preferred methods for family planning. (I am assuming we're discussing two married Jewish people who need some time between having children. If someone is engaging in risky behavior, well, if someone said "rabbi I like to go out on Saturday night, eat cheeseburgers, and play Russian Roulette", the rabbi would tell them to first stop playing Russian Roulette and then we'll worry about the cheeseburgers later!)
Rabbi Alfred Cohen discusses it in a situation where one half of a married couple has a sexually-transmitted disease. ("Married - With AIDS", Journal of Halacha & Contemporary Society, c. 2011?)
I am not aware of other discussions on it, either in writing or orally (though perhaps I'm not listening in the right places). The article quotes Rabbi Woolf so you'd have to ask him.
In the early 1980s, the concept of an English-language halacha journal was somewhat novel; Rabbi Alfred Cohen (editor of J. Halacha & Contemporary Society) asked Rabbi Yaakov Kaminetsky whether it was a good idea: "Yes, and you need to write about birth control! Today everyone assumes it's all prohibited, so when they do it anyways, they use the halachically-worst methods." That rings quite true in light of what you've linked.
(Rabbi Hershel Schachter tells the above story, concluding that many rabbis at the time were afraid to publish on birth control, or "family planning" at it was known then. Eventually he wrote the article on it.)