Triplets over 8ths

Ok so my piano teacher is going through a piano rock book and one of the rhythms is like this:



I tried over and over but my left hand is the problem, i think. First I played the rhythm each hand seperate which is just natural for me now but when I put them together, My left hand wants to play swing 8ths instead of straight 8s, and I cannot get it to play straight when I play a triplet, I listened to a midi but WHen I try to play it be ear even my left hand feels like it's playing a swing rhythm and I can't help it, how should I time these?

Andrew has actually a very good video about that, those type of things are called polyrhythms btw, here's the video on that topic:
https://www.youtube.com/watch?v=CXQjFRU83gU