[40isthenew20]

My wife's personality is very similar to what the OP described. It used to drive me nuts when we were dating because I wasn't sure of exactly what the situation was. I was attributing her 'coldness' to not being into me seriously, but in time I realized it was just her being her.

Nearly 20 years later, not much has changed, but I do now that she loves me and just is not as affectionate as I am in certain ways. (Yeah - even us men like to hug and kiss sometimes.)