Love is important when considering marriage. But, it is not everything.
There will be days when you will feel madly, crazy, head over heels in love. Then, there will be days when you are tired of the other person and just want a minute by yourself.
You have to remember that marriage is about commitment, through everything!
The way I see it, marriage is 100/100. There can't be 50/50. Each person needs to give their all.
On days when your spouse can't give 100%, you make up the rest. If your wife has a 80% day, give 120%.
Make sure that you are ready and willing to go the extra mile and that the other perons will do the same for you before considering marriage.