Can I marry my boyfriend even though he doesn’t want to become a US citizen

OK so if you're a US citizen, then you can sponsor your boyfriend for a fiancée visa and then after he receives the fiancée visa he enters the United States and you must get married within 90 days and then you can apply for his green card. He is not required to obtain a citizenship if he has acquired a green card. Consider working with an attorney here in the United States to process your case from start to finish. Some of us charge a very affordable flat fee with no hidden costs from representation from start to finish, and counsel in any state can represent any client from all over the world.