OMG you are all so so lucky to have the help if needed! My nearest relative is 6000km away on the other side of country and all though we moved away it would be nice occasionaly to have some help...with housework of cause LOL!
Even when i had DS who is nearly 7 and we were within a few hundred kms, i only ever had him looked after by DP's sister once for a couple a days while we had a getaway when he was 2yrs, and all i did was fret for the two days until he was bad in my sites so it wasn't even a getaway!
I have always done it on my own with DP and i just couldn't imagine it any other way. I'm certainly not judging anyone, but i don't think you should base your decision for a third on the presumption you will need more "VILLAGE" help, you would cope no matter what because that is what you would have to do....no choice, just do what you have to do to get it done, where not supermums!