I haven't rtft yet, as should be working! But...I am not maternal at all, don't find other people's DCs endearing - I can objectively say that one is cute or laugh when they do something funny etc but I don't feel any particular warmth towards them.
My DS1 was a bit unplanned
but I honestly thought he was the most beautiful child to have ever graced the earth when he was born, he was clever, funny etc. He was never very cuddly or affectionate (showed ASD traits from an early age) but I felt like I'd done a pretty good job with him, so went on to have 2 more.
My DCs are wonderful, I love them to bits, I don't gush about them or expect anyone else to find them as riveting as I do, but actually lots of people do tell me how funny and clever they are, which is reassuring - I am doing good stuff here as an unmumsy mum!
I work as a childminder, which is an odd choice for someone who doesn't love kids, but actually I find it helps me to be objective as I see them all the same, there's no favouritism and I am utterly professional with them, as a teacher might be, rather than a family friend or aunty etc.
The only stumbling block is with my DP's DCs as he is very gushy about them, will sit and say 'ah look how adorable she looks' etc and I find it difficult to express my feelings on that. To me, even my own DCs aren't 'adorable' and while his are lovely, I don't see them often enough to have developed any kind of bond, so being with someone who desperately wants to share those loving parental pride moments is hard, especially as he DOES seem to love my DCs 
But I would say, other people's DCs and your own are a world apart, so don't worry about it!