Complex sentence: Meanwhile, Hardy Jenns (Craig Sheffer), Amanda's Corvette-driving spoiled ex-boyfriend from the rich section of town, plans to cause trouble for Keith; although he has no real feelings for Amanda, he feels humiliated at losing her to a social inferior.
Split into simpler sentences: Meanwhile, Hardy Jenns (Craig Sheffer), Amanda's Corvette-driving spoiled ex-boyfriend from the rich end of town, plots trouble for Keith. Having no real feelings for Amanda, he nevertheless feels humiliated at losing her to a social inferior.