不是蝴蝶飞不过沧海,而是沧海那边从来没有过等待 英文。

Not that I haven't tried. It's you that never waited for me.
不是我没尝试过，是你没有等我。

直译蝴蝶沧海什么的，老外听不懂，中国人看着也不伦不类。

究竟想表达什么意思？英文讲究精确，不擅长表达含蓄和意境。所以先了解这句话想表达什么信息再翻译比较合适。
直译如下：
Not that butterfly cannot cross over the sea, it is that the butterfly is not waited from the other side.

Not that butterfly cannot fly cross the sea, it is nobody waits her at the other side( of the sea).