既然你在想着别人那为什么要和我谈恋爱呢?

Now that you are always thinking of
others,why do you still talk love
affair with me?

楼上翻得什么啊。

Since you are still thinking about someone else, why do you want to begin this relationship with me?

这才是翻译！
Now that there is another one in your heart, why do you still fall in love with me?

So why you fall in love with me without loving but give it to another?

人家来帮忙总是好的，英语的学习过程中，错误根本就不可避免，大家宽容点。

Since missing somebody else, why are you trying to fall in love with me?