D' abord tu as deux phrases, and these phrases are called in english ''compound sentences'' so you must use a conjunctive adverbs to make one and only one phrase , tu dois relier tes 2 phrases afin d obtenir une seule phrase, so in order to obtain that you must a conjunctive adverbs , the best one would be '' in results'' because as a consequence of what your friend did , your friendship with him is over , as everybody knows about the ''cause/consequence''. and i think the best one would be '' he didn't apologise for what he did to me;in results, our friendship is over. we must also use a semicolon before a conjunctive adverbs, so now i put together the two sentences and make one in final. in conclusion , it always depends on the sentence to translate something. i hope my answer satifies your question .