What is the theme of the poem "Love and a Question" by Robert Frost?

I think one of the themes in this piece is
sacrifice.

This stranger seems to be travelling through the
night on a weather-laden day. He asks the bridegroom for a place to stay for the night,
but the bridegroom likely has plans for his woman this
night.

So, he considers what he was willing to
sacrifice:

The bridegroom thought it
little to give
A dole of bread, a purse,
A heartfelt prayer for the
poor of God,
Or for the rich a
curse;

These things a little food or
money or even a prayer would be easy to give... and the bridegroom would be willing to
give them. The sacrifice of a few bucks far outweighed the sacrifice of this night he
has possibly waited for a long time.
The ultimate question came when he
considered:

But whether or not a man was
asked
To mar the love of two
By harboring woe in the bridal
house,
The bridegroom wished he
knew.

He knew if he brought this man
in, he would do so unwillingly and he would be disgruntled about it. It would be killing
his chance to express his love the way he wants to on this night. That is not something
he wants to sacrifice.

Other themes to consider might be
decision-making, or types of love.