Beautiful is a perfectly good word for describing a guy!
I understand how it may sound odd as it’s been more used towards females, but it’s not gender specific, so yes it can be used towards men.
And also, even though I have to agree that pretty is more feminine, my friends use it all the time to describe an effeminate man, but only usually in this case. If you see a handsome man whose quite manly, it’d be weird calling him pretty in his entirety. You can say, though, that he has features that are pretty, like eyes or lips and what not.
All in all, yeah you can use beautiful or pretty to describe men, depending on how you’d like to use the word.