@Tarheelgurl: First, it is great that you are trying to have the finances conversation before getting engaged. Many people do not have this discussion (even before marriage) and it can be devastating to a relationship.
Depending on how he was raised, his parents may not have taught him or modeled good financial practices. That does not mean he cannot learn (as long as he is willing). You should calmly explain how important this is to you and the future of your relationship first.
With that said, if you do decide to get married, you two TOGETHER need to agree on a financial lifestyle. It may be a combination that is more moderate (some saving and some spending), but the important part is that you compromise and agree on something you two can stick too.
It will be tough, but try to sit down in a nuetral setting (maybe even outside the home if possible–a coffee shop) where there are no distractions and nothing that would add pressure or a sense of urgency (do not do it on a busy day).
Have all of your financial information handy like total income, bills, debts, etc for both of you (credit scores would be a plus as well). And then lay out what a typical month and year would look like. This should be as accurate as possible, including rent, utilities, expenditures, food, gas, entertianment, etc.
Then talk about what each of you has in mind for financial goals. Do you want/need to make a large purchase (i.e., a car, house, etc)? Do either of you have a large amount of debt (i.e., student loans, credit cards, car loans, etc)? What are your income prospects in the next year or two looking like (i.e., unemployment, student status, significant increase)?
Then agree on what each of you thinks is reasonable for savings and working toward large purchase/goals. You may not both contribute equally (depending on the difference in income).
This will not necessarily be easy, but it will help you start the conversation and get on the same page. My Fiance and I have done this more and more lately (about 1 a month) and it has helped tremendously. We have been together for 9 years, but did not start doing this until about 8 months ago.
You do not have to have joint finances or even share a household together at this point to do this, it is about communicating, compromising and agreeing on goals together.
Hope this helps!
ETA: My Fiance is a bit of a spender and makes half of what I make. We are not wealthy, but combined sit around $70k a year. It has been difficult at times, but he is starting to come around and rein in his spending/minimizing his debt. His mother has made very poor financial decisions throughout her life and so he has developed some interesting habits. But through communication and work, we are heading toward a stronger relationship and a better financial situation.