Sabotaging my relationship... or time to go?

I feel a little silly writing about this, but I've been driving myself crazy so I am going to give it a go. I am 50 years old and have been single for the past 10 after 3 failed marriages. Ironically, I have been seeing a 55-year old man who has also been in 3 failed marriages (his last ending a few years ago). It would seem logical to assume that I would be hesitant to get married again, but since I met this man (8 months ago) the opposite has been true. I was happy while I was alone, but now that I met him I have been an emotional mess. I love him and care about him so very much and feel certain that he is "the one." He says he feels the same, but he thinks that we should take things slowly and be careful, considering our pasts. He never thought he'd get married again, but since he met me he feels less sure, but he's scared of going through a divorce again. I understand this...I'm scared too, but feel so sure that this is right that I'm having trouble coping with his hesitation. He feels like time will fix things...that we'll stay together and after a few years he'll have more confidence that our relationship will last and not be afraid to get married. It sounds so logical....and I know it. He has introduced me to his family, taken me and my daughter on family vacations, and has invited us to his holiday celebrations. I know he cares about me and is trying to build a relationship that includes a future together, but I am obsessed about this marriage thing. It makes me miserable. What if we spend years together and he still won't want to get married? Can I do anything to make myself be happy with just having a "boyfriend"? We are not living together and because I have a young daughter I am not really considering that an option at this time. What I want is to be happy with what I have and to stop thinking about marriage. Any thoughts on how I can stop driving myself crazy?