Kantian ethics would almost definitely say to never divorce. Kantianism is not the same as Rule Utilitarianism!
Even if we ignore for a moment the fact that Kantian ethics doesn't say anything because it's not well-defined, it's not at all clear to me that this is true. As it stands, your statement sounds like it's based more on popular impressions of what Kantian ethics is supposedly like than an actual attempt at Kantian reasoning.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.