It sounds like you guys are dealing with it well. Your daughter is still a baby after all, and it's a huge change. That your wife was able to go to her made your DD feel safe and loved. Every preschool is different, some are ok with parents spending some time there; others prefer you disappear so the child can blend in. I'm guessing this is a full day program? If so is it possible to sometimes go for lunch with your DD and the other kids?
And talking with your DD about how nice the school is, the exciting things there are to do there (without being overly effusive) is helpful. Having the dialog about how daddy spends his days, how mommy spends her days might suggest to her that now she has "her" day, with important activities that are slightly separate from the family, but the family gathers together at the end of the day is a concept she'll grasp.
Hope it all gets better soon, sending support!