It works for guys too, not just girls.
It doesn't have to be an insecurity to evlove into that. All it has to be is a person going and doing things without telling people where they are going. Not calling when you say you are, or not returning calls for days at a time is a sure fire way to arouse someone's suspiscions. Not answering your phone repeatedly, and/or sending someone to voicemail at odd hours during the day is another good one. Especially if you weren't doing it previously in the relationship.
That isn't really an insecurity persay .. it's just someone's suspicions being aroused over recent strange behaivor.
And it happens a lot. People may not even think they are doing anything wrong .. but that's not always how it is being perceived on the other end.
People need to step back a second and put themselves in the other person's shoes every so often and think "how would I feel if it were me and he/she was doing that?".
Usually .. the other person would probably come to the same conclusions .. But .. most won't admit it to the other person because they feel slighted that they've been accused of something.
And so the problems start.
Doesn't that just constitute a bad relationship and time to get out anyways? Wouldnt you be doing the above mentioned because you have lost the original spark of the actual relationship? Thats what I have always seen that as anyways.