A book that I read (per my significant other's request) was For Women Only. It's a book that helps get inside the male mind. While it's mostly geared toward Christian married women, it still could help. And it will help if you're writing a Christian Married Man.
Okay.
Here's the thing.
You need to stop thinking of it as "I can't write this MALE character!". Are men and women different? Yeah, a tiny bit. But like, who cares if your friends say your OC doesn't talk like them? Different people have different speech patterns and different experiences that shape them. If they talk a bit flowy, maybe that's actually backed up by something in their lore? Like, I highly doubt a royal would speak like your typical teenage boy (assuming who your friends are, sorry).
Just embrace it. Let the character develop themselves, like I did with mine, through roleplay or writing short stories or something.
Don't make them a cliche. If they're in a relationship, don't make the relationship cliche.