There are often very simple alternatives.
Using “So”:
“We marry because that way we can provide for children.”
“We marry SO we can provide for children.”
No Conjunction necessary:
“I am anxious because tomorrow I’m getting a new head.”
“I am anxious. Tomorrow I am getting a new head.”
Reorder clauses:
“We divided the children in half because we wanted to see if they were good people on the inside.”
“To see if they were good people on the inside, we divided the children in half.”
Using “Since”:
“I am hungry all the time because I am a zombie.”
“I am hungry all the time since I am a zombie.”
Using “Therefore”:
“I do not believe in zombies because I don’t see how they can exist.”
“I don’t see how zombies can exist, therefore I do not believe in them.”