Your OP is very familiar indeed to me! And in the odd idle moment in the middle of the night it did occur to me to worry about something along the lines of the first pp as a reason, but never seriously as DP is the kindest, loveliest, most honest and caring person I've ever known. It was just SO baffling why she had such a strong preference for me always.
I used to sometimes ask DD why she didn't want daddy, she sometimes said she didn't know, sometimes said because he could be a bit shouty (he's not at all, but I guess he is 2% shoutier than the massive softy that is me), other times she'd just say she does love daddy and want him but she loves and wants me more.
I think it's just one of those things. For whatever reason, maybe labour +breastfeeding+maternity leave, DD bonded very closely with me in the first few months and I don't think anything else will overtake that bond for a few more years. DS is similar now tbh.
I enjoy being loved so much, but I do find it very tiring being pawed at so much.
I find it heartbreaking when DP wants to be loved this much and isn't. That in turn is tiring.
He finds me moaning about being touched out hard to deal with as he's not exactly jealous, but you get what I mean!
Fwiw DP and I share childcare pretty evenly, we both work 4 days and have a full day off with children each, at the weekends etc we share pretty evenly too. We do a good mix of all together, one child each, one of us away and the other solo.
All I can think is either I'm just a much nicer person to hang out with, or else the intense 24-7 bond created in the first few months is stronger than any amount of fun and effort from DP as soon as he was able.
It's just one of those things. I'm sad for DP and glad that he stays positive and keeps putting in huge effort to make the children love him as much as they do me for just being me.