Like everything in life there are no guarantees. Society has this perception that with marriage and relationships there is this cookie cutter way of life. People meet, they fall in love, then they marry. No one really tells you what happens after that.
Marriage does not guarantee a lifelong relationship, but neither does any relationship ... And only marriage was designed to be a lifelong relationship. The only reason it is not is because we have made it that way. We too often look for any easy way out. If we feel unhappy, then just leave. If you feel unfulfilled, then leave. If your husband makes you mad, you can just leave.
Everything in life is work and is needed on both sides. Love is an entity that consumes us all at some point or another. With the sweets come the sours, this is something that every person will realize in time.
"Love is a friendship set to music.”
Joseph Campbell