Yes, there are opportunities available for EFL teaching in elementary schools (and even kindergartens) abroad. Spending a few minutes Googling around I don't see anything recent for Bolivia, but you might have better luck. There are opportunities elsewhere in Latin America, though. One website says it might be easier / better to look for jobs while you are in-country:
ESL in South America Your boyfriend might be able to let you know about availability where he's living, or if any schools are hiring.
You'll get some good experience teaching kids, but there will be some differences, of course, between teaching overseas and in your home country. You probably won't have anything to do with the administrative side in Bolivia: no calling parents, no paperwork, no event-planning. Likewise, depending on the country you choose you may find more lax standards, so you won't go through the numerous background checks required of teachers and volunteers in the US.
But there are plenty of resources available online for teaching EFL to kindergarten and elementary school students, and you'll be able to adapt some lessons you'd use in your home country to what would be appropriate there.
Best of luck.