Meaning of 添い遂げる in this sentence

Question

What is the meaning of 添い遂げる in the following sentence?

それがすべてを背負い覚悟してきた人の最初で最後の自由ならば俺も添い遂げたい。

Context: a man agrees with a friend's request to act freely, without worrying of anything.

The only meaning I found in dictionaries is to remain married/together for life, but this cannot be the case. I think here it has a meaning similar to follow, could it be? Here's my attempt:

If this is the first and last time a man that had the resolution to carry everything on its shoulder acts freely, then I'll follow him.

Answer 1

If these two people are not in a romantic relationship, "to follow" may be appropriate. But the important connotation of 添い遂げる is until the end, or usually, until death. Maybe the friend has little time left to live?

There are other compound verbs which include 遂げる:

• 成し遂げる: to accomplish something difficult (after much struggle)
• やり遂げる: to do something all the way to the end

As you can see, "consuming much time/effort (to do something)" is the meaning of 遂げる as an element of a compound verb.

Answer 2

I think here it has a meaning similar to "follow", could it be?

Yes, I would say that you are on the right track.

In this context, 「添{そ}い遂{と}げる」 is being used as a dramatic and exaggerated word choice to mean "to get in the same boat".

In fact, the whole sentence sounds extremely dramatic. It is not something you will hear in the real Japanese-speaking world at all.