You are worrying too much over nothing.

Parts wear down, some faster than others. But it will happen, and no it's not because of your strength. Keeping your parts well maintained is the best thing you can do to keep them working for a long time. Chain stretch is caused more by grinding than tension. When your chain gets dirty it will start to grind down the hole in the plates that the pins go through, effectively ovalizing them. The chain doesn't actually "stretch," it's just that the holes get larger as they wear.

Snapped chains are almost always caused by improper installation (or not replacing a worn chain). If you bent one of the plates while pushing the pin in it will weaken the chain. In this case being strong will exasperate the problem, but strength is not the source of the problem.

Get some decent quality parts. Make sure they are stiff. This doesn't make them stronger or more durable, but if you are as strong as you say you are then you will notice frame/crank flex more and you'll appreciate the efficiency that stiffer components will give you.