If you were not witnesses then nothing you did would have been considered inappropriate between two adults and certainly not unsurprising between an engaged couple. You confessed some of what you did to the elders and they also did not deem it worthy of anything other than a reproof.
You need to talk to your fiancee about what he is thinking at this time. This level of paranoia and guilt is unhealthy in a relationship. After all if you are to be married then you need a level of maturity that neither of you are demonstrating. It is very easy when placed under such scrutiny for love to turn into dislike. It is easy to look at the other person and see in them the cause of your woe. Has the balance of your relationship changed and is it worth calling a halt to proceedings to allow you both to determine whether you want to go ahead.
If he is already convinced that the marriage is doomed then what sort of wedding day will it be? You are adults not children and as adults you take responsibility for your own choices. It will certainly be unlikely to succeed if you constantly involve elders in the intimate side of marriage. A husband needs to know his own mind and be prepared to stand up for you, not throw you under the bus to satisfy his ideas of what is nice and to salve his conscience. You also need to think about your own self worth and self respect, how much humiliation are you prepared to take for this wimp.
I would take time to evaluate whether this can ever work.