1. Having leather and darker woods is always a great start to make him feel comfortable.
2. Grey hues will work with every colour that you decide to put into the room (even the feminine colours!)
3. Some fabrics/textiles that will work well are burlap, leather, basket weaves, metal, and reclaimed woods.
4. Let him have his own inputs as well. He lives there too!
5. Big pieces of art work for him, maybe he's into old movie posters or aviation? Incorporate his hobbies into the space.
6. Or even give him his own man cave? Far away from the rest of the house!
7. I know most men aren't fond of too many throw pillows, so take it easy with them! He will want to cuddle with you not the mountain of pillows.
A place to check out masculine art pieces that could suit both your styles are Restoration Hardware and Country Furniture.