If you love your life right now and don't want it to change then don’t have children. It will change your life and your priorities beyond recognition.
This can be hard enough for couples where both really want children. But he doesn't. He is just letting you down gently by saying he's not sure, because he loves you and doesn't want to hurt you. And of course he knows how unfair biology is, that you only have a few years if you want to do this. While he has the luxury of decades of fertility and multiple chances.
And he doesn’t want to say no and deny you what he already has. That feels very unfair. But that doesn’t mean he actaully wants children , he would only be doing it for your sake.
He likes your life as it is. having all your attention , your long lie ins and adventure. No doubt he loves your pre pregnancy and childbirth body. The spare time, cash and all that freedom.
He knows he will lose that all.
I assume he is planning too retire in a few years, so he will be a SAHP and your will be working full time to provide for your family. How will you both feel about that?
Will he be happy and competent to take on that role? Does he do 50% of everything ( i mean everything ) right now?
A lot of men of his/ my generation are ok to “ help out “ but expect the woman to do 80% of the work and 100% of the planning / management / responsibility . If he does that you will end up burnt out and very resentful.
Financially - are you able to live off your wages and his pension and support a child for the next ? 25 year , when he is 85? ( Im guessing 2 -3 years from now to birth and 22 years until your child is finished education ). Have you done projections with your financial advisor>
Realistically, as soon as your child leaves full time education ( and your are 63 and 85), you may well be your partner’s carer. Very few 85 years olds are travelling the world and having great adventures.
Age gaps between couples tend to feel bigger and not smaller as the years go on.
Finally I fear that if you go ahead with this and have a baby, your partner will soon decide that its not for him. So you need to be prepared to be a single mum.
Im sorry I wish I could be more encouraging and say go ahead, it will all be fine.