so I'm kind of iffy about spending time with girls one-on-one for dinner, or a movie,
You should stop doing this kind of thing when you have a girlfriend, a live-in partner or a wife. You are opening yourself up to unintentional emotional affairs when you go on one-on-one date like activities with members of the opposite sex
It's common practice to stop acting single when you're in a committed relationship and to stop putting yourself in the company of other women without your SO joining you.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion