I’d recommend to meet first and see how well you blend as a couple.

For him to move to the US he has to either marry you and then while living here and waiting for green card he won’t be able to legally have a job and you’ll need to be able to support him until then. Can you support a man for a year or more?

Other option is for him to obtain work visa. He needs to have the kind of job that US would issue work visa such as engineer or scientist etc what does he do for a living?

Another option for someone with EU passport is come and stay in the US for 3 months or so but he won’t be able to work.

Where are you two planning on living? Who’ll support you two?

You two need to discuss all that.