Most Helpful Guy
You heard from him how well the last 2 marriages worked after a short time knowing them. You also know what the definition of insanity is, right? Doing the same thing over and over and expecting a different result? Like several have mentioned, he's taking his time to get to seriously know you before making that step. He's matured, and protecting himself. Divorce is exceptionally difficult emotionally to handle, even for guys.
He was honest enough up front. You obviously see something worth while in him. Don't be surprised if he realizes after a couple years, he feels comfortable enough to offer you a ring. Take things one step at a time.
Most Helpful Girl
He probably realized that because he married his last two girlfriends in 5 minutes, that's why he's not married to them still. Lol I don't see this as him wasting your time, I see it as him being more mature and realizing that it takes more than "5 minutes" to get to know someone and decide to spend the rest of your life with them.