The Sacrament of Reconciliation

What is the deal with y'all needing a priest for salvation? Recently I was confronted by this question by one of my non-Catholic friends. At the moment I didn't really know, but I told him about the sacrament hoping that that would help him figure it out. But I realized that I really should know why so that I could fully understand the sacrament.

What I found really enlightened me. First, there are two kinds of sin: mortal and venial. Venial sin does not sever your relationship with God, it only damages it. So, technically, you don't need to go to confession for those sins. Those sins get forgiven over time and prayer with God. An example would be your friend keeps on asking you to go to his house and you tell him that you have homework and he sees you going to your other friends house. Your relationship would be hurt, but not severed. Over time he would forgive you by you going to his house a lot. You still have to apologize, but not as severely.

However, mortal sin is different. The sin has to be bad, you have to know its bad, and you have to freely choose to do it. If all of these conditions are true, then you have severed your relationship with God. It would be like if your girlfriend or boyfriend asked you to go see a movie with them and you told her you couldn't, but then you went with one of your friends and he or she was there and saw you with someone else. They would most definitely break off your relationship right on the spot. Of course this a bad example because it isn't God that breaks off the relationship, its you. For these sins you must go to confession. The Eternal punishment of you defying God gets forgiven through Reconciliation, but the temporal punishment is still with you forever saying I severed my relationship with God.