Is it true that the ml had a child with another woman even after meeting the fl?

The ML met the FL in their 20s and he had a child with another woman in his 30s (10+ years later). The ML has to have a heir so he married 3 concubine because he always thought his love for the FL will be unrequited forever. But the ML has a very good platonic relationship with his concubines, he also got divorced with all of them long before marrying FL. FL also has a great friendship with all the concubines and they remain supportive of her even years later. Overall this manhwa have no "antagonists" other than the occasional annoying men. It's really giving found family vibes.

Thanks, but didn’t one of the concubines die while giving birth? Also, do you recall what chapter they got divorced?

Yes! That concubine that died is the only woman who had a child (a daughter) with the ML. The divorce between the other 2 wives and the ML happen at around starting from ch134 maybe, I'm not so sure but the wives already filed for divorce at ch140 and the divorce was never mentioned again. The ML is already single at that point