How do you non custodial parents cope???

Seriously, how do you cope without being able to kiss your children when ever you want to, or peek in on them when they sleep. It breaks my heart when I think about it. I couldnt live without my children on a daily basis. I would probably go a little crazy. I understand that you shouldnt stay in a relationship for your children, you need to do whats best for you also, but I understand why some people put up with a terrible relationship. The alternative is to move out and not have access to your children at will. I have a friend who is going through a divorce, and he is really having a hard time coping with this. His soon to be ex was really tough about visitation at first, but she has realized what its doing to him, and her children and she had a change of heart, so he could see the kids whenever. But he is still really depressed about not being able to put them to bed, or tell them there bedtime story (which was his thing sice they were born). So, how do you cope???