The nicest hotels that accepts singles in the Ocho Rios area are either The Jamaica Inn or Royal Plantation.
I would check with Couples resorts to see if they would let a single stay there if they are part of your wedding party
They will let a single stay at Couples, for a wedding, but at a double room cost.
Also, there is a cost to spend time on the Couples resort if you are not staying there. I think it's $200 per day. They also pro-rate for the wedding or 1/2 day. Either way, you have to pay extra money.
Resorts nearby---....you can find maps online, just do a google search for map of hotels in Ocho Rios, Jamaica.