Question for the guys... serious answers only. thanks!?

my bf and i have been dating for almost 5years now. but i moved out of the country 2years ago for work. and we havent seen each other for tht long. both of us decided to remain exclusive and have a long-distance relationship bec we realy want to marry each other when i get back home. its realy hard. but i love him so much and i know tht he loves me too. i even told him that if he cant handle this kind of relationship, then we can break up and i wud understand. but the thing is, would he last that long w/o having, u know, . i know i shud trust him but i need a guys point of view about this. if u love a girl and plan to marry her, wud u really wait and remain faithful?