I've been dating a woman for a little over a year, very casually at first, but our relationship progressed a lot, partly because she had a major life event happen that involved us having a lot of really in-depth conversations and sharing of emotions about our lives. She is an objectively great partner and person: no drama, emotionally stable, makes sound financial decisions, values health and wellness, has an internal locus of control, self-aware, etc. There has been no major conflict in the entire year we've seen each other, and when there are things that need to be hashed out, we've been able to discuss them very maturely.
All that being said, I am having a very tough time seeing myself marrying this woman or us combining lives. I don't really understand why exactly either, but it's just very hard for me to envision, and if I am being honest, I feel like I don't want those things with her. I like her, but I also don't feel like I have "passion" for her. I have had relationships in the past where I did feel those things and like the woman I was with gave me tremendous inspiration and motivation, like I felt this jolt of energy to conquer the world for the woman I was with. I don't really feel that at all for my current gf, even though I can recognize intellectually she's a good partner.
We have started having conversations about the future, our relationship, etc, and I don't really know what to do. We only see each other about twice per week, and it's hard for me to see our relationship progressing beyond that. I have considered suggesting a break, but I know those often don't go well.
Any advice?