I'm a person who needs solitude much more than company (I've heard that's the main difference between an introvert an an extrovert) so I can really relate to the need you express. You can get what you need without your relatives becoming miffed, without making excuses, and without having to apologize for being who you are.
This is what I've learned about getting my needs met, using four steps of a system called Non-Violent Communication:
1. Acknowledge what feelings you hear the relatives expressing about their wish to be with you (or your hunny expressing about his desire to have his relatives come visit).
2. Tell what you feel, what is most alive in you.
3. Express your needs clearly and without apology (just be sure they are needs, not demands).
4. Make a request without making excuses for it.
In your case, this might sound something like, "I hear so much generosity in your offer to come stay with us for a week. I love it that you are looking forward to this new baby and are willing to give up so much of your time. I'm also feeling anxious and overwhelmed by the prospect of having people in my home during a time when I look forward to quietly connecting with my new baby and recovering from the delivery. I believe I will do much better on my own for the first couple of weeks. I would love to have you come to the hospital to welcome the baby, if you wish to do that, and I'm asking that you delay visiting our home. May I call you when I feel ready for visitors? Maybe I will even discover I need your help. Thank you so much for offering."
Very few people would have the nerve, or the cluelessness, to push their way past such a request, because you haven't tiptoed around the topic of what you need for your own wellbeing, and you have graciously acknowledged their interest. Again, it's important NOT to apologize for what you need, and NOT to make up reasons why the visits shouldn't happen. Reasons can be argued with. Needs are much harder to push aside. The word "AND" is really helpful, too, as in "I hear what you hope for, AND this is what I need." You can use the same techniques for establishing the length of visits when you tell them you are ready.
If you'd like more tips, here's a handy NVC process chart:
http://www.nonviolentcommunication.com/aboutnvc/4partproc...
My best to you and your new experiences as a mama.