看了看一些回答，突然好奇为什么有相当一部分人的道德底线已经到了觉得同时谈两个女朋友不是什么大事的程度了。这样的欺骗做法会严重影响人与人之间的互相信任，并使怀着真心与人交往的人对爱情与关系失去信心，具有严重的负外部性，因此并非简单的私事。
对于说这样损人利己的做法属于理性、这么做的人多就没问题的说法……现在新冠全世界感染的人那么多，也基本没见到国内有谁说新冠不是病的吧。
至于什么“谁能完全不犯错”，这个答主确实无法保证，但是答主有信心说，自己在未来任何时候、任何情况下都不会出现同时与多个女生以恋爱关系交往这样的严重欺骗行为。如果出现这样的实锤，无论是否存在“合理借口”，答主愿意接受任何形式的舆论、道德或法律的审判，并愿意承担包括网暴、社死在内的一切预料到或未预料的后果，且允许任何人在实锤后曝光本人的任何文字、朋友圈和聊天记录；即便对本人的伤害远远超过此行为的严重性，也不会因此声称其有任何不妥。
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/* "The author" refers to Cheng. */
I am not an expert in the field of personal relationships and know little about Cheng's stories. Nevertheless, I still have some confusion in his statement.
(i) Since the author (Cheng) has been in an intimate relationship with his ex since high school, and he also claimed that they "overcame numerous challenges" during the years, it looks unreasonable that their lives naturally became "divergent" and the breakup was "inevitable" merely due to the distances. If the author does cherish the love that has witnessed their growth over the years and is indeed serious about the relationship, he should make some commitment or at least try to fix the gap instead of prematurely abandon it. If the author did make these commitments but failed, he should state more about it to show that he was truly devoted to that relationship to excuse his cheating behavior.
(ii) It is unreasonable for the author to state that he "had some dating by chance" at the time he still had a girlfriend. No matter how that relationship was going on, it is unacceptable and immoral to have a date when already in a relationship. This is a common sense for any civilized human, and such major violation could never have been "by chance". It can be inferred from this statement that the author either was not that devoted to the relationship with his ex as he stated (which constitutes cheating), or is overlooking the fundamental morals of a civilized human being. I wish that it is the former case, though.
Overall evaluation: Strong Reject
