Scared to admit to fiance I don't want more kids

My partner and I have been together for a year and both have two children from our previous marriages.

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We recently got engaged after he popped the question on a weekend away, and I couldn't be happier.

There's one big fly in the ointment, though: he's keen to have another baby and I'm almost certain I don't want that. He's mentioned it a few times, usually in a lighthearted way, but it’s playing on my mind.

I want us to go into this marriage with honesty and no unfinished business or resentments. I'm worried if we have a serious sit-down chat about kids, then it'll mean no marriage and no relationship.

Our children are all eight and under, so I feel we have enough on our plate, but if we were to try for another baby, time is running out, as I'm 37 and he's 39, although age isn't an issue for him.