In addition to what you're saying (as I fully agree with it):
Even when both sides are being honest, relationships that work at distance don't necessarily work IRL. It's hard to deeply know someone through the internet, even with VR; and in this sort of situation we tend to fill the gaps with idealised crap, instead of reality. Then as you meet the person IRL you discover that they aren't anything remotely similar to what you hoped for.
I met my wife in an mmo and the first 2 years of our relationship were online. After 3 years I moved to live near her. We have been together for about 18 or 19 years now so if you actually communicate it can work.
Yup, with a LD relationship like that, you have to fill in a lot of blanks about someone that you can't determine - how are they in the morning? Do they pick up after themselves? Do they have any gross habits? There's tonnes of little things that are entirely irrelevant in a remote setting but can really make a difference in person.
And naturally when you fill in those blanks, you tend to only fill them in with positives or you just don't think about all those little things.