You might want to consider Manzanita, some 24 miles south of Seaside. It's a very quaint small town with all the ammenities that Arch Cape lacks. The beach is about 7 miles long and one of the widest you'll find along the coast, which, even in July, makes it easy to be by yourself, which I equate to romance.
There are a number of cottages available, several of which you can find here: http://www.neahkahnie.net/
I can also recommend The Inn At Manzanita (http://innatmanzanita.com/). It's a block off of the beach right on the main street (Laneda Ave) and a VERY nice facility run by some really nice people.
The afore mentioned Oswald West State Park, the beginner surfing capital of the north coast is just 4 miles north and alos offers wonderful hiking and some of the most beautiful scenery along the entire coast.