What impression do you get about Antonio and Bassanio's relationship based on Salerio's description of their parting?

Salerino, not Salerio, tells of the Bassanio and Antonio's departure. Salerino refers to Antonio as a kind man. He describes how Bassanio says he will hurry back. Antonio tells him not to rush his courtship but to take all the time he needs for the relationship to ripen. He says not to worry about the loan from Shylock that he has taken out, but simply to concentrate on having a good time and on wooing his beloved. After Antonio says these brave words to Bassanio, he tears up, overcome with emotion. As Salerino describes it:

And even there, his eye being big with tears,
Turning his face, he put his hand behind him,
And with affection wondrous sensible
He wrung Bassanio’s hand. And so they parted.

Solania, his companion, says:

I think he [Antonio] only loves the world [life] for him [because of Bassanio].

As some scholars have pointed out, Antonio's affection for the younger man seems to surpass the bounds of friendship. Antonio's two friends describe him as having very strong feelings toward Bassanio. Some have argued that Antonio goes to such risks to get money for Bassanio because he is in love with the younger man.

The speech gives a clear impression of mutual affection, since Bassanio eagerly tells Antonio that he will try to return quickly. However, it's clear that Antonio's feelings about Bassanio are more noticeable to Salerio, since he mentions seeing him cry and shake Bassanio's hand "with affection wondrous sensible"—"sensible," in Renaissance English, meant "capable of being perceived," so, in other words, it was easy to tell that Antonio was having a lot of feelings. The strength of Antonio's feelings for Bassanio is not surprising, given that "Antonio" was an Elizabethan slang word for a gay man; for another Shakespearean "Antonio," take a look at Twelfth Night! But Antonio is clearly a self-sacrificing person when it comes to love; he encourages Bassanio in his courtship, telling him not to think about Antonio's peril: "let it not enter in your mind of love." He knows that having a rich wife will be advantageous for his beloved, and he is not going to stand in the way of Bassanio's making that happen.