just don't love you anymore. (誠懇但是太傷人心)
我不再愛你了.

It's really not working. (有理有據(jù),還算婉轉)
我們的感情真的行不通.

I've met someone else. (簡直是找死,人品不行啊)
我已另結新歡了.

We've grown apart. (喲,這個不錯.理性!)
我們都各自成長了.

The magic's gone from our relationship. (太"文"了,好像演戲)
我們之間的愛情魔力已經(jīng)不見了.

I think we should be just friends. (夠直接,意思表達得很清楚)
我想我們應該當朋友就好了.

It's not you, it's me. (好!自己承擔后果.有大將之風)
不是你的問題,而是我自己的問題.

I really don't wanna be tied down. (確實是理由,萬不得已的時候再說吧)
我真的不想被綁住.

You're really too good for me. (這個不錯,婉轉,一般都用這個)
我真的配不上你.

You don't really love me anyway. (哈,夠直接了)
反正你也不是真的很愛我.