The hard thing in an existing relationship is to maintain an emotional connection without physical closeness. When you know what it’s like to be with someone, it’s harder to be away from them because you know what you are missing.
Two hard things that couples face in a long-distance relationship is the lack of physical intimacy and distrust. Lack of physical intimacy can lead to cheating, and lack of clear communication can prompt jealousy. Cheating, jealousy, and distrust, in general, are outcomes of an unhealthy relationship.
It’s better to prevent them before they happen by maintaining a degree of understanding via effective communication. Because once a person acts on their insecurities or desperation from unfulfilled needs, the relationship becomes a lot harder to fix.
Your long-distance relationship gets hard when you start having conflicting feelings. We all feel insecure at times. But when the stress from doubts becomes your norm, it can lead to anxiety. At this point, your relationship is no longer healthy, as too many doubts and confusion get in the way of enjoyment and fuel insecurities.
The hardest part here is not being able to talk it over with your partner face to face to see if your doubts have reasons to be. Sometimes doubts are not based on anything specific and are products of insecurities.