This is indeed a red flag and you should ask him about it.
If he is truly your boyfriend and you both had a conversation to be exclusive to each other before you got into a relationship, this is a red flag that you shouldn’t ignore.
There should be no reason for him to have an online dating profile if he is dating you exclusively.
Allow your parents to share in the process of communication with these guys online.
In other words, as you begin to get to know a guy online, let your parents know about who you are talking to and give them some insight into the guy’s personality and background.
If you find that there are some similarities in both your background and that of the guy that you met on the online dating website, you should also share this with your parents.