Other possible email:

"Hi H,

I agree, that it would not be appropriate to bring up this situation at the wedding.

Unfortunately, because of the dog I am not staying in ciy of wedding and I cancelled the room reservation so I did not receive a fee.

The wedding is at xx time at xx location.

I had planned to get a gift on my own but if you would like to buy a gift together, that is fine. Their registry information can be found on their website at www.website.com. Please let me know what you pick!

See you at the wedding tomororw - it should be fun!"