What do you think of his reasons for wanting to marry you? Since I am a man, I will try to answer from that perspective. You decide if I am right or wrong with my way of thinking.
1. A woman, aged 33, whom I assumed to be attractive, recently divorced and available is an excellent pick for a 63 year old widower. Where sex is concerned, I believe it ranks at the top. So, sex is definitely my first priority in deciding on wanting to marry.
2. By marrying, I get exclusivity of your companionship 24/7/365, which is different if you are just a divorcee.
3. As a wife, an a young one too.. I will be looking forward to the day when you will need to take care of me, when I am old and feeble. That should happen in 10 or 15 years down the road, hopefully later if I do not have any health issues.
4. Chances are, you will be financially dependent on me, and also your twin daughters. And chances are, because of that you will cater to my needs and wants. I doubt, with our age difference, you are marrying me for love, more for someone to take care of you and children, financially and offer a stable home.
5. My grown up and married daughters, will be more than happy to have someone like you to keep me company (and also to take care of me, see above) when I grow old. But, on the flip side they will be watching how my wealth will be distributed when I am gone, don;t you think they will be concerned?
I am sorry if all these sound so negative, but it is as blunt as black and white is about life. Think carefully, enjoy the pre-honey moon before accepting the proposal.
Good luck!