Do not let feelings of guilt factor into this. You need to do what is best for you and your career. Your company will fire you in a second if its best for them. Loyalty is dead.

Would this be an issue for a man?

Just to put some perspective...I was at my old job a long time. They allowed for a lot of flexibility during a family crisis etc. I was offered another job, turned it down because I felt a strong sense of commitment to my current job and the manner in which they supported me. Then there was a change of management,power struggles within the organization a lot of major changes and not for the best. Eventually it was obvious I needed to leave as things were going down hill quickly. When I finally found another job I had a lot of resentment toward my old job because I felt the new management really let me down especially after all of my years and dedicated work ethic that was no longer something of value to the new management. So I guess what I'm saying is I wish I had left while I was on top and things felt good instead of staying too long and leaving on a sour note.

I'm in the same place as you OP, right down to the commute. Things with the potential job are moving faster than I expected and basically I'm scared of making the wrong choice. Also, my current job is being really awesome right now about some flexibility I need for family reasons and I will feel like a jerk if I quit right afterward.

I've found it a little helpful to make a list of circumstances under which I would / would not take the job (if salary was x I would not, unless perks were y), and also to make a trial run of the new commute to see if it's really that great.

I've been there, it's a normal feeling. Don't worry too much until you actually get the offer. Then you can weigh the pros/cons of leaving.

I sense that I'm close to getting a job offer from somewhere, but I'm now having some cold feet. I really like my current job, but the commute is killing me, so I thought I'd dip my toe into the market to see if there was something that might be a better fit. I interviewed at this place and they want me to come back for some testing... (second round). If I pass, then I could have an offer.

But now I feel intense guilt about leaving current employer.

I like this new company, just minor panicking...thought it would take longer...