You are past due for some open communications on what is going on and what your expectations are for marriage. One thing I can tell you for sure is that a ceremony and a marriage certificate will not change who you and your fiancé are. It won’t suddenly make problems go away but it will make unwinding the relationship more costly and difficult if that’s the way things are headed. If there is a medical reason that your fiancé has lost interest in sex there may be a medical solution. Your fiancé needs to speak honestly with their doctor about this. Some antidepressants can have this effect, but there are multiple antidepressants available - some with more or less side effects. And it can sometimes be a matter of timing as to when they take the medication and when you might want to have sex. I can also tell you that as a person who was formerly on antidepressants - The best treatment for depression usually includes both counseling and medication. If possible, the patient may find that counseling leads slowly to a solution that makes the medication less necessary. The biggest problem with antidepressants, like any medication, is that the body builds up a tolerance to the medication requiring higher and higher dosage to achieve the same beneficial effects - But the undesired side effects can get worse with the dosage increases. Regardless of what issues, medical or otherwise, your fiancé may have; you need to ask yourself if the present situation is good enough for you and your relationship that it’s how you want to spend your future? If you cannot say “yes” to this question then you must at least postpone the wedding until the problems are resolved or call it off.

I don't understand people. Have you discussed this issue with her? Why don't people discuss stuff like this? How can you even contemplate marrying someone if you can't communicate with her?

Have you talked to him about it? Perhaps he's waiting until the wedding night so it will be like your first time? Maybe he's going old school. :D

Good thing you're not married yet. Let him know your concerns and that you will have to put the wedding on hold until the issue can be addressed.