I would more think that she is also afraid to let go because she knows you & the other guy she really doesn't know other than having an attraction to him. Depends on if she has much self-confidence (which it sounds like she doesn't)...especially since she sounds pretty dependent on you.

If she's ever going to figure herself out.....she needs to be totally ON HER OWN & have to do the things ON HER OWN or figure out how to get them done without YOU being there.

Sounds like she needs to GROW UP a LOT.....but that can also mean that she does grow away from you.....or she may also realize that you are the one that she does want to be with.....but sometimes you have to let go completely & let them get that figured out on their own. Know that it feels like keeping contact keeps the feeling of her needing you (or you being needed).....but sometimes we really need to sort things out ALL on our own & figure out where we really are coming from & where our HEART really is.

It's scary to leave if you have never been on your own & know that you know how to take care of yourself & the messes that life throws at you....but she needs to learn......it will make her a better person in the long run....& if she decides that your marriage is what she wants....it will probably make her a better, more responsible wife....IMO.