OP is right,you should be getting righteously married under god and following the laws of the bible. That will help you maintain the marriage.
Getting the government involved is a whole different story,but the act and ceremony itself is a beautiful thing,and a powerful declaration.
But its not about being scared,if you are scared maybe you just have knowledge of self and know your limitations. You don't have to get married by law,but it should be a mans top priority to settle down and build a kingdom and legacy.
You need to be searching and willing,while you are young though. You want to find someone who after a few years pass,you see they still put forth the exact same effort that they did when you two first got together. Alot of people,both men and women start going off fumes and just go through the motions after only a year in.