Review the item:
Clyde knew that he should be saving money for next semester's
tuition he spent every paycheck, however, on
gold jewelry and expensive dinners for his greedy girlfriend Gloria.
A comma splice occurs when two complete sentences are incorrectly joined with just a comma. In the example above, no such comma exists. Clyde knew that he should be saving money for next semester's tuition is one sentence. He spent every paycheck, however, on gold jewelry ... begins the second sentence.
Because only empty space exists between the two, you should call this error a fused sentence.
To fix the problem above, you could put a semicolon between tuition and he.