I'm sure this has been asked a million times before but please bear with me.
DP are expecting our first child in October, and are in the process of buying a house together. We will make wills ASAP to ensure each other inherits the other's half of the house should one of us die (so one of us isn't left homeless with our child).
I see lots of posts on mumsnet where people say things like "I can't believe how dumb some women are, leaving themselves exposed by not being married"/similar and I need to know...what does this mean? What should we be doing to protect our child/me/DP? Sorry if I'm being dumb 
I don't want to be one of these "dumb women"; be brutal, what's the worst that could happen a) to me if DP died, b) to our child if I were to die, or c) if we split up?
What are the practical implications of being an unmarried parent (other than having to provide identity docs when taking child abroad, etc.)?