Don't expect your groom to know anything about planning a wedding. He may think that once he proposes he's off the hook as far as wedding responsibilities go until the big day.
It's not his fault that this is the way he thinks planning works - that it's all on you, the bride. But it's up to you to tell him if you need or want his help. Don't expect him to jump into a wedding theme and color palette brainstorming session or just start calling wedding vendors to get pricing information and availability.
If you want his help, after all it's his wedding too, then be clear from the beginning of the process that you want him to be involved and meet with vendors or even research certain vendors and wedding details.
Don't let the wedding day be a complete surprise for him. Part of the fun is planning the wedding so take him with you to appointments and some wedding shows and enjoy cake and champagne together. It'll be a big help to you to have his input and support when making tough decisions, like what color the linens should be. : )
There are some great wedding sites just for guys that he's sure to enjoy. Forward him any or all of these links:
The Man Registry
Temple of Groom
Ben the Groom