They feel like they have missed so much that they want to "catch up" as soon as they can.
My husband was like this after his first deployment. He wanted to go everywhere and do everything. His second and third deployment, he wanted to stay home the first few months with just him, me, and our girls.
There are a few things you can do. First and foremost though, you will need to tell him how you feel. Tell him that you don't want to stop him from seeing his family, because then he can be upset with you for "stopping" him from seeing his family. But that this is how you feel. Then these are the things that you can do:
1. You can go with him and just suck it up. Tell him that you support him and that is why you are there. But don't argue with him the whole time you are seeing family or be upset the whole time you are there. Try to act like you are enjoying yourself.
2. You can tell him that you really don't feel like going (but I would at least go with him once or twice) and that you really need to stay home with the baby or have him take the baby with him. So you can get some time by yourself and he would get time with his Son and some of his other family members.
3. You two can argue about him not going. And he doesn't go and he will be upset and that will cause more problems later for the both of you.
I doubt that he will be able to go his first weekend home because he should have a distance he will not be able to go beyond until he gets leave.
Again, the only thing I can offer is to talk to him. The most important things in a marriage especially a military marriage is communication and then trust. You need to be able to communicate with each other about how you are feeling and then trust that the other will listen to what you have to say and act accordingly.
But you both need to listen.
Know that you both will need to take some time to get to know each other again when he comes home. That it won't happen right away and that he might feel like an outsider in his own home and with his own children. Let the baby bond with him and also important you two will need some time without the baby to bond again. Have a date night, go out and have some fun without the baby.
Again, I know you know where he has been and what he has been doing. I know you want your time with him and to him to spend time with his son. But he has other ideas to.
Good luck
http://www.nmfa.org/site/PageServer?pagename=home_reunion
http://www.aacap.org/cs/root/facts_for_families/coming_home_adjustments_for_military_families
http://www.ehow.com/how_2143470_readjust-family-life-after-deployment.html
http://www.research.va.gov/news/features/deployment.cfm
https://www.usaa.com/inet/ent_utils/McStaticPages?key=advice_deployment_coming_home_main
http://deploymenthealthlibrary.fhp.osd.mil/products/Returning%20to%20Family%20Life%20After%20Military%20Deployment%20(234).pdf
http://www.armywell-being.org/skins/WBLO/display.aspx?mode=user&ModuleId=8cde2e88-3052-448c-893d-d0b4b14b31c4&action=display_page&ObjectID=a904d15d-36ae-4313-878f-f7b04f13b86c&AllowSSL=true