Given how unpredictable IEIs are, I doubt SLEs would ever get bored.
Just imagine this...When an IEI senses that SLE is losing interest in them, the IEI with victim romance style will start feeling insecure and start withdrawing from SLE and go completely cold on the SLE, hence subconsciously playing a game of push-pull. This push-pull game would then trigger SLE's conquering mode, and the SLE would start to go all their way out to woo the IEI all over again, hence reassuring IEIs that their interest in them is constant and haven't wavered.