Line a baking sheet with parchment paper and set aside.
Place white chocolate in a microwave-safe bowl and microwave in 10-second intervals, stirring after each interval.
Place candy melts in separate microwave-safe bowls and melt in the same way, stirring after each 10-second interval.
Pour the melted white chocolate onto the prepared baking sheet and spread it out into a thick rectangular shape. Add dollops of melted pink and blue candy. Swirl the colors together using a clean spatula to create fun patterns.
Add marshmallows, sprinkles, and heart candies while the chocolate is still melted. Refrigerate until set, about 2 hours. Break up bark into large, irregular pieces.