Forgive me - I have ALOT of history behind me and tend to identify with things too easily sometimes...
he has two other children with another woman who he obviously left; for you? if so, be wary of your relationship, especially in the next year as you learn to cope with the routines and isolation of being a SAHM and getting your body back. don't expect any type of commitment from him.
If he takes more pride in his son than his other children simply bc he's a boy, be wary. He may not value women (you, his daughters, his mother) highly or as highly as men (himself, his son, etc). If so, he will consistenly choose his son over you if this is the case.
Whose idea was it for you to be a SAHM? Is it something you've always wanted? If not, consider carefully what you DO want; not what you think is best for your boyfriend or son, but what you WANT.
From experience, given that you are so far away from family and friends, and now isolated from any work colleagues, it would be very easy for your relationship with this man to become a very controlling, even abusive one. Make sure you have solid boudaries your don't allow him to cross. Don't give up friends, family, relationships with people outside your household.
Again, forgive me if I'm overstepping my bounds.
Congratulations on your precious boy!