I know how you feel. My DSD1 is very huggy with me and it feels quite natural to have her snuggled up to me on the sofa (although it often ends in DD's jealous tears
)
DSD2 barely looks up to say hello/goodbye and at bed time is usually so busy calling after her dad that even when I do hug and kiss her, she pretty much blanks me. It doesn't come naturally because the relationship with her is very different.
It also annoys me as DP seems to miss the times when I am affectionate to her and just sees the second attempt when I say goodnight from the door and presumes I haven't actually tried to kiss and hug her. I don't think it's that she doesn't want it, she's just not really fussed one way or the other.
My DD always hugs and kisses anyone DP, but he doesn't really know how to approach my DSs so just gives them a manly nod and a wave at their bedroom door, which is a bit of a shame as DS2 is a great hugger and thinks the world of DP, but although they have computer games loads in common they just don't have that physical closeness (possibly because DP only has girls, he doesn't really know how to be affectionate to boys?)
I have mentioned that he shouldn't feel awkward about it as I'm sure DS2 would be happy with a hug, but I would never push it.
Do whatever feels natural to you and tell DP to butt out. If you want to hug them and vice versa, it will happen, having him tell you to do it is out of order.