Complex sentence: Upset from Alvin throwing a surprise birthday bash, to his dismay, he decides to take his lover, Samantha, to Florida for one of his client's album release party, instead of taking the Chipmunks.
Split into simpler sentences: Upset from Alvin throwing a surprise birthday bash, under his dismay. Deciding to take his lover, Samantha, to Florida for one of his client's album release party, instead of taking the Chipmunks.