I'm thinking if Iris is from the future at the end of S2 Iris will go back to the future with Mom West/Wally and Barry will go to prison, or at least I hope that's what happens.
I can see it now Iris is started to fall in love with Barry, Barry feels the same way then out of nowhere bam Iris founds out she's from the future and needs to return to the future, and Barry feels he needs to let her go back home with Mom West/Wally and Iris feels she needs to let him go so he can focus on being The Flash and saving the city.