It's not a matter of what and who expects, but it's a matter of what you like or dislike doing.

There are such options.

1. There are guys who like blowjob, but in response they do not do cunnilingus, they do not do it at all.
2. There are guys who like blowjob, and in response they do cunnilingus, but without pleasure.
3. There are guys who love blowjob and are happy to do cunnilingus.

Then there are the same three categories, only those who do not like blowjob, and three more categories in which guys are genuinely indifferent to blowjob in general. And a bunch of subcategories. :)

I emphasize that what is important is what is normal or positive for you during your desire to please your partner, and it does not matter that someone expects something from you.

Some smart guys start strangling girls during sex, because they say they've seen enough porn and thought they'd like it. Girls, almost everyone with whom they do this turns out to be in shock. But it is not necessary to draw an analogy between lovers of asphyxia and lovers of oral caresses now.

Blowjob is great when the one who does it is happy, and the one to whom it is done is delighted. Only such a scheme is ideal :)

I wish you good luck and hope you find a solution :)

Options.

1. Do you have to join Peace Corps? If you can give up this idea to be with him, then this is one of the options.
2. Why doesn't he come with you, joining Peace Corps too? Could he give up his plans for 2 years to help you in volunteering? Therefore, this is also a good option, unless, of course, by the phrase "it's not the route he wants to take" you meant that you had already discussed it.
3. You can ask him to wait for you. If he is a man of honor and can be responsible for words and promises, regardless of circumstances, then this is also an option.