I couldn't tell you about a good relationship, but I certainly found that having children massively brought to the surface issues in my bad relationship 
On a serious note, though. I reckon that if your relationship is going to survive/get better on having children, you need to instinctively work as a team, to communicate, to approach all joint things - housework, finances, career decisions which will affect household income, etc etc as fully equal decisions and responsibilities, which does not mean designating one area to one person and the other "helps", e.g. with housework. You both need to value each other's contribution, and not be competitive (you're not working as hard as me). You need to be able to recognise when it's time to pick up the slack, and be happy to do that, and not resentful. You both need to appreciate the other picking up the slack when they do and not take the piss.
You need to be able to laugh, and to discuss things without arguments, and to talk when things are less than great and find a way forward together. You need to deal with stress in a healthy way.
It really helps to discuss the basics and ensure that you have a similar enough outlook to get you past the main issues - for example, if one of you is really strict and the other is much more laid back you're going to wind each other up over discipline issues. If one of you can cope with mess but the other is super tidy you're going to clash on this. If one of you is quite hippyish and AP leaning (cuddle babies when they cry etc, keep them close, breastfeed on demand) whereas the other is more routine minded and teaching them independence young, that stage is going to be hard. You need similar or complementary values, too. Imagine you have an 18 year old - what things would make you feel you'd failed, and what would make you feel you'd done well?
I agree totally you need to want children, not have them just because it's expected. What do you want, as individuals and as a couple? Would you be sad if you didn't end up having children? Have you thought about the effect on your, his, or both of your careers? Have you thought about who would take time off, really thought about it, including the possibility that you may want to go back later or, indeed, earlier than you thought?
It is rewarding, I won't deny that, and seeing your child with your partner and the adoration they have for each other is wonderful, as is seeing how they take on their traits as they grow up (this could also be a negative - worth thinking seriously about!) but it is a big decision and it will definitely have an effect on your relationship one way or another. Good luck! :)