He has gone far, but I am still here.

Because there is no direct translation of "in situ" in English, or it is not pleasant to hear, and it rhymes directly.

Or:

He has gone away, but I still stay where I am.

He has gone far, but I didn't move.

This may be more to your taste:

He has gone away, and I am still here.

He has gone away, but I am still the same.

He's gone, and I'm still here.

Here, the taboo generally means to keep, wait, and sometimes it means to endure.

This sentence can also be said in reverse:

I'm still here, and he's gone away.

I'm still here. He's gone.

I am still here, but he has gone away.

I'm still here, but he's drifting away.

Similarly, other sentences can be reversed, just remove "but" and add "although" or "return".