My girlfriend struggles with being in a D/s dynamic in a long term romantic relationship. Has anyone else experienced this?

Me [M24] and my girlfriend [F27] have been together for 4 years now, and we love each other deeply. We are both interested in exploring a D/s dynamic that comes with rules, daily tasks and rewards. I want to be the dominant whereas she would be the sub.

The issue here is that it is very difficult for her to get into subspace while in a relationship. She has seen that in a more casual dynamic with someone that is purely sexual, it is much easier. However, because she lives with me and we both don’t want a 24/7 dynamic, it makes it harder for her to separate our loving normal selves with a stricter control focused one.

It is not a problem because of my personality or my lack of skill in this regard, as I have messaged her posing as an online Dom for a while and she loved that. I came out to her about that and although she was angry at first we worked it out, and it proved to the both of us that we are compatible in this way. She is also Demisexual, so it is not a problem with looks.

I am curious if anyone else struggles with this in their relationship? And if there is any way to help it? She is going to start therapy this week and I have been in therapy for a few years now. Is there any changes you think me or her should make?

This is a sensitive topic for the both of us so please be kind, and our utmost priority is to figure this out together.