Hi: I'm currently reading this book by Neil T. Anderson, entitled "The Bondage Breaker." I believe this book will answer all your questions exactly. I've had that same though before and it's true that satan exists. In fact we Christians are in a spiritual battle all the time. We may not notice it but satan is always at work trying to decieve us to stray from God using the simplest everyday matters of life - you know, i.e. that voice inside your head saying it's not important to go to church, better to stay in and sleep.. This book discusses about spiritual warfare that is happenning around us. if you are not devoted to God, it is already victory for satan because he's goal is already achieved by leading you away from God and that is why he don't need to temp you anymore. that's the point. So, is that what you want? the scriptures says in 1Cor.10:13 "...God is faithful, who will not allow you to be tempted beyond what you are able, but with the temptation will provide the way of escape also, that you may be able to endure it."
James 4:7 " Submit to God . Resist the devil and he will flee from you."
I encourage you to Get the book. It's your answer.Promise!!
Godspeed.