The female MC went to a beach house during her school break. She was there for some day and then the male MC came. They grew up knowing each other but don’t often see each other. The first time they met each other was at someone’s wedding/party. The female MC has like the male MC since they first met. Seeing the male MC again at the beach house, her feelings grew. After they spend some time together at the house, they had sex. The first time they did it was outside, by the shore. Everything was good until the female MC family came to the beach house. It was revealed that the male MC isn’t the person she thought he is. The male MC is actually the twin brother of the person she fell in love with. Problem arise but it’s soon revealed that he is actually the one she fell for but she mistakenly thought it’s the brother that she likes.

Please help me with finding this manga. It’s shoujo, and it has smut scen too.