Boyfriend already had 2 kids, Advice!!

Ok so I have been dating this guy for about 5 months and I really love him, he is such a great guy the only thing is that he has 2 children already and has full custody of them. The mother of these 2 kids is not in the picture because she abandoned them basically.  I do love children and hope one day I have some but I always wanted to just have kids with only one person and them only have kids with me.  It's just a personal preference.  Has anyone ever been in this kind of situation and how did you handle it?