You are just experiencing the common issues of online dating it is not a poly problem. Visit the forums of many dating sites you will see the same issues.
Rule 1... Nothing is real until you meet
Rule 2... Do not invest too much time in email and texting.
Rule 3... Do not fall for a fantasy. People can tell you anything you want to hear. Watch the TV show Catfish.
Rule 4... Be safe. Physically and sexually.
Rule 5... Stop actively searching. Just have your profile out there. Good things come to those who wait.
40 yo straight female
Married in the eyes of the government to Butch since 2001...
Murf my monogamous second husband has been with me since May of 2012.
In a V relationship with an average 60/40 split of time. Only due to Murf's and Butch's crappy work schedules.