Marriage is a complicated journey for many people. Some people get married to someone that they are madly in love with and envision an entire life together filled with kids, rainbows, adventures, and sunshine.
Others marry someone to settle down and do what they are supposed to do but realize the love just isn't there. Others get married and realize it's a mistake. Then, there are those who get married and their love might grow slowly over time. But the point is: it's different for everyone.