The first conclusion to draw is that Kevin is an a-hole. Maybe Ms. Fits was an ideal mate for Kevin because she could nestle nicely into the landscape of his life. Or maybe fate, and his overeager seed, forced him to make her fit.
But the second, more important conclusion is that a person has to do more than complement your life to make love last. A relationship should be so emotionally snug that you feel comfortable, lusty…and able to keep it in your pants.