OK, I'm a betrayed spouse, so much of this is coming from my experience going through recovery with my wife. She had two PAs and one EA and I've tried very hard to understand the dynamics behind all of them.
All this is just my unlearned opinion.
I think the "state" of the wayward spouse's mind is the same, "I found someone who meets my needs better than my spouse and I am willing to give up my marriage to be with them."
The tendency to re-write marital history, view their spouse as inept at meeting their needs, give the "I never loved you" or "ILYBINILWY" speech, etc, is the same.
What I think is different is the lengths to which the wayward spouse will go to "justify" or "protect" the relationship once the emotional/physical line has been crossed.
Most of us were raised that marriage was sacred, that infidelity was wrong/evil and good people don't do such things.
For a spouse to engage in an "emotional" affair, they entertain thoughts, feel feelings and have only imagination as their "memory". It would be easy for them to "wake up" from their attraction and walk away once they got a peek through the fog. Society, in some wacked out circles, even encourages such wandering as healthy to a person to find what is missing in their marriage so they can live a more fulfilled life. Rubbish.
When the two infidels engage in any physical interaction based on their attraction, kissing, fondling, sex, they know they have done the "unthinkable" in most people's minds and to justify to themselves that they aren't "evil" or "wicked", they will go to greater lengths to berate their spouse and marriage and assassinate the character of the faithful spouse. They want to make the marriage, in a fog-filtered historical-rewriting sense, to be unbearable and pat themselves on the back for staying as long as they did. They not only weren't doing something as horrible as they were raised to believe by cheating, they were getting something they deserved.
It seems to me that this is the biggest difference. Sure, there are all sorts of physiological things that the act of sex includes such as chemical imprinting and "good feelings", but I think those only add to the need for the Physical Affair infidels to justify themselves as not wicked more than the Emotional Affair infidels.
Just my $.02.