If everyone thinks that relationships are build based on giving love ,not for taking then trust and sincerity comes,then none will dishearten anyone.Trust is like taking a chance.Sometimes we may be lucky,sometimes not.For a true relation ,we should dedicate one another.You trusted other people unconditionally.Its almost impossible for a wise person to do so.Its also possible to trust conditionally with your eyes open.You kept complete confidence in other that he willnot cheat you.Relationships are sometimes built on compromises and faith. I think those who brokes the heart of people loving them are treacherors or cheaters.You had faith,trust and love in others.if you are unhappy in a relation ,you should avoid him.When relations being boring ,feeling jelous one feel very less loving to other.Different people trust different one in different level.You are using heart.When it collapses by cheating ,it really hurts.the most common reason i believe is lack of communication in relationship or a change or perception and desires or just an utmost stupidity and selfishness.love hurts and life is not easy its not ment to be.we may feel hurted today,but a wise thinking man moves on.he never cares much abt pain.people act according to the situations.You may not have realized that.May you depend others more than should.I think you dedicated to others in time ,but they used it and never loved you.To trust anyone is not a sin or crime.But you should see ,if they are worth trusting.If you misjudje a person for that,it will be a crime to yourself and you will be the victim.People may use you for their own sake.they may have exploited you.You may have trusted them with your eyes closed.They may never value your love or feelings.