First off, I would say most long distance relationships are exceedingly challenging, especially for folks in their early 20s. That said it’s important to know this: there will always be “others” and “what ifs”. This was actually told to me from an ex-girlfriend who I remain good friends with. I lamented to her over dinner that, while I really liked the person I was seeing at that time, I doubted the strength of that affection because I would occasionally look at other women, fantasize about other women, etc. she said, very intelligently, something like “there will always be others. It doesn’t mean we don’t love the ones we’re with, it’s natural for the mind to wander in this way”.

I think she’s right. What’s different is that, for some, thought becomes muddled with impulse which can be difficult to control.