Miss,
My ex was pretty much the same way. She just seemed to be able to 'turn it off' and I was envious of that ability to not feel so deeply. She wasn't seeing anyone, but her secret life of pills was about to be exposed and she 'ran'. Once gone, of course she wanted to portray herself as happy and "getting her life together." (though she never explained what that meant)
I remembered something my best friend says about relationships, however, and I believe it holds great truth, not only in a relationship where the dynamics of addiction exist, but relationships in general.
"Compatibility can not be determined until pathology has been exposed."
New relationships are exciting and 'feel good'... and isn't 'feel good' that addicts seek anyway? Any mechanism that 'feels good' relieves guilt, shame, etc and distance gets you out of his face. Regardless, our pathology and individual dynamics have to be addressed or we continue the same patterns... addiction or not.
'Feel good' goes away and pathology is ALWAYS exposed. And, in my opinion, we can only determine the quality of our relationships and the amount of investment we should risk in them once we have been exposed to another's 'true self'. 'Feel good' fades and the honeymoon is over, but pathology is forever unless a conscious, sustained, focused, invested effort to change exists... without a desire to change, it's one constant pursuit of diverse mechanisms that lead to 'feel good'.
An addicts decision to pursue 'feel good' isn't a statement about who I am as a person... it's a statement about who they are as a person, living out their own pathology. "... and the wisdom to know the difference." It's freeing when I can take responsibility for what is mine and allow others to own what is theirs.
It takes time, but it does get better.
Many Blessings,
Shaman