Despite my rep here, I've been happy and faithful to my INTJ for over 10 years. When I met him, I knew I'd be hardpressed to ever find someone who'd love me and accept me as unconditionally as he does. And he is the *only* stable thing in my life, something I very much treasure as it provides shelter from the chaos that is my life at times.
I will admit, as I am very much driven to connecting with people, that the intensity rush you get from meeting someone new,and it clicks really well, is...tempting. But I've yet to meet another man who can give me what he does and it becomes harder every year as we've build up a beautiful life together, and a very strong and sound relationship. And I would never be able to live with myself if I hurt him in any way. Though I've met other men that can make my heart beat faster for a while, and I enjoy that feeling, I recognize it for what it is: a fleeting feeling, in no way able to compete with the feelings I continuously have for him
So, the answer to your question is 'yes', imo.
The answer to the question: 'will she ever stop scanning the horizon?', in my case, is no, as it's in my nature to constantly search new opportunities and experiences in *everything* In this case though, I mostly do it to learn more about who he is as well as who men are in general