Snowball, I think you need to sit down together and you need to start the conversation by admitting you did something out of character that you perhaps shouldn't have. Tell him that you felt he was not being honest with you at the time and before accusing him of anything needed clarification, which you got by opening the letters. Make it clear that you are aware that both of you have in fact done something that has upset the other and both of you have not been honest. Tell him you really want there to be total honesty in your relationship and feel you need to know what is going on. You are after all telling him what you have done, so that he too knows the truth. With everything in the open you can then rebuild the trust that is being lost through this current situation. But please don't just brush this aside, as it will grind on you and endanger your feelings and relationship. Try to remain clam and try to keep the conversation low key and friendly. You are as much to blame for the current tension as he is ... you are both not being honest and open. So, be strong, take the first step and if he starts giving you a difficult time about the letters, don't forget to remind him that you are not the only one who has done something you shouldn't have. After all, had he not been so secretive and denied any knowledge, you would not have had to open the letters. Honesty is always the best policy in any relationship! Simples! Best of luck! I really hope this works out for you.