Did this person not know that you had children?
This should be disclosed in your profile (of course, if you’re meeting in person, you have to decide when to disclose.) If you didn’t have it in your profile, some people will consider that deception.
Some portion of men will not date a woman with children, others want to. In between are a portion who take each partner on a case-by-case basis. That group (which I’m assuming is the largest), you can work on influencing their decisions with careful strategy.
Yes he knew very well that I had kids