我们彼此深深的看着对方用英语怎么说

He stared at each other deeply.

这里指的深深地并不是真正的深深,而是情深,深情地, 所以,应该这么说:
We are looking at each other lyrically

We looked at each other with deep affections.

lyrically是抒情地的意思,deeply也有深情地之意.
故应为We stared at each other deeply.
或者We deeply looked into each other's eyes.

We looked at each other deeply.

we look at each other deeply.

顺便对老V亲说一下，deeply可是表示深深的意思，与提问者要求的原句更为符合，而deep才是真真的（形象非抽象）的深