I married a man with the same age difference, at the same age. I only had one child from a previous relationship (and was single because my first husband left me for another woman after we discovered that getting pregnant a second time was difficult).
We had pre marriage relationship counselling and he was adamant that children was not an issue for him, my child "was enough" for him.
You can guess the rest, when he reached his mid thirties and his mates all started to have children he wanted to try, so I agreed but by this time I was in my early 40s and my heart wasn't in it. He said it was fine, he was happy, would never leave. But, he did, for the sake of having "his own children" he'd already lined her up and got her pregnant before he asked me to "release him to find someone to have children with". He said I'd never let him be a father to my son, but he'd known from the outset that my son had a father and spent half the week with his dad. He didn't need a father, he already had one.
It's easy to think one knows what one wants in the future but the reality is that we can't predict how we will feel about things as we age and life stages change. If I were advising me at that time now, I'd say don't marry him. Definitely Don't merge finances and see what happens.
I hate being a harbinger of doom but I wish mumsnet had been around and I'd posted your question at the time. I might have saved myself a lot of money, time, heartbreak and friends.