I received a letter that posed a question about a very controversial topic...What should I do if my significant other wants to have an open relationship?

This topic has received a lot of attention lately with Chad Ochocinco being very frank and open with soon to be wife Evelyn of Basket Ball Wives about being with other women. Back to the letter:

Dear Supreme:

I have been with my girlfriend for 4 years and engaged to her for the last 2. We are supposed to get married in two months but I don't know if I can do it. We had a converstaion last night and she asked if I would be willing to have an open relationship. I don't even know how I feel about her anymore. What would you do?

So, I want to know what would you do? Would you consider having an open relationship with your significant other? Do you think it's the answer to happy relationship?