How do I get this man to take me seriously and marry me?

You've begun to mature, and he's noticed that and trusts you more. But you're not to the point yet where he would consider a real, committed relationship. Apparently, the only thing you had going for you for the first 2 years was the , otherwise he would be gone. Now that your acting in a more mature manner, you can see that this guy requires a certain level of maturity before he would consider a real relationship. And the more mature you become, the more he'll let you in.