This had a bit of conscripted army humor. Girls giving up on waiting for their boyfriends to finish their compulsory service and dumping them over the phone or by message is an infamous conscripted army cliche. Since everyone is young, the bonds aren't that strong, and most 18-21 year old girls can't be arsed to wait several months just to see their BF again or aren't satisfied to just see them once every few weeks on leave. We had a guy go AWOL to go and kick the ass of the guy his now X-GF left him for.