I guess it just depends on the man,My mum had children befor she and dad got together,and dad loves us ALL so so much.
On the other hand,my partner has told me straight up he loves me but if i had children already he wouldn't be with me,same as any other woman.
Which makes me feel good cos his ex is now a mother,so i have no worries there :)
But i do respect his choices and I love him for it.