Screening for potential LTR and this was brought to my attention. Upon asking about her father (whom she loves and respects) the conversation moved to how did he meet your mom. Turns out the mom met the father while the mom had a boyfriend. Father asked her out and when she declined he stated it was "just as friends". You can see how that played out, multiple kids later.

Would this be a red flag? My gut (which I know is a man's guiding light) says that because of this she will still be open to other men even while in an LTR, it's how her parents met.