A recent article, from Yahoo's 'Dating 101' series describes these 5 factors that make a man ready for marriage:
1. The Capacity to Love
2. Being Able to Accept Imperfection
3. He Truly Believes in Commitment
4. He's Sure He Can Be the Man
5. He's Tired of Playing Around
Again, these aren't my points, but the argument made is an interesting one.
My take instead, is best paraphrased from the late and great Dr. Randy Pausch regarding knowing if you (male or female) are ready and 'this is the one'. Pausch says, you know you have true love when 'their (your partner's) happiness is more important to you than your own'.
Truer words were never spoken on the subject in my experience. Please pass along your own sentiments as advice if you have some. If it helped you, it could help others in a tough situation.