Sleeping babies

My friend once said about children (especially young children) that they need to sleep the whole night through so that parents' tolerance and patience can be charged back up. It gets depleted and worn away during the day (with tantrums / unrealistic demands etc) but once they're asleep you stare at them and are filled back up with tolerance and adoration. After I've put them all to bed - then found whatever piece of plastic tat toy they want to sleep with, closed / opened the door at the right angle, and have the right music on at the right volume I then let out a sigh of relief that my tolerance / love can be charged back up. I often find myself in the evening, going to check on my 3 boys and just staring at how calm, peaceful and obviously gorgeous when they're asleep. Its a habit from when they were babies to check that they were still breathing. I think the threat of cot death was so drilled into me at the hospital with son 1 that I'm still scared they won't wake up. Even when one of the boys sleeps in the urge to check on them is quite strong (its v.rare with son 1 to sleep in, not so much with son 2 and the baby) and often leads to me waking them up. Its a habit that means the other night at 4.50am I suddenly realised I hadn't checked on the baby (ok not a baby at 19 months) so woke up hubbie to check whether had (he hadn't) so jumped out of bed to check on him and woke him up in the process. Will I ever learn??