When you marry, keep as much of ‘yourself’ as you can. Keep your family links, your friends, so that s/he doesn’t take your whole life when s/he leaves.
Don’t let his his/her family fill you, make sure you have as much space for your family as s/he has for his/hers.
In this way, your entire ‘support’ system isn’t controlled by your spouse.
Don’t ever think that your spouse and in laws are ‘forever’. Considering the Divorce rate you have less than a 50% chance of having a successful marriage.
When his/her In-Laws absorb you, so that at YOUR BIRTHDAY the entire room is full of his family and not one of yours, it is time to hit pause.
It is time to insure that never again are you the only one not genetically part of that group.