For those who use the American English Standard, “for ever” doesn’t exist in the contemporary lexicon and would be considered a misspelling of the one-word “forever,” which can either be an adverb or a noun. As an adverb, “forever” means for a limitless time, as in “Only a fool would want to live
forever”; as a noun, it means a seemingly interminable time or excessively long time, as in “It took Nancy
forever to get herself dressed for her first date.”
Since I know you to be based in South Africa, however, you must have had greater exposure to British English than to American English. I therefore presume that you know that while the
Oxford English Dictionary cites “forever” as the predominant usage, it also recognizes “for ever” as an adverb that—like “forever”—also means eternally, continually, or incessantly. You will find an interesting discussion of the usage of “for ever” in Patricia T. O’Conner and Stewart Kellerman’s
The Grammarphobia Blog.
Despite the fact that “for ever” is still extant in the British English lexicon, it has progressively gone into disuse. I don’t think it will be missed if it finally goes into total oblivion. After all, “for ever” is pronounced in practically the same way as “forever,” and, whether you are using British English or American English, writing “for ever” in your correspondence or published work today will surely mark you as a diehard noncomformist.