I've enjoyed these the most. About the only thing that would interest me. Keeps it fun and fresh with some level of commitment. The guy still has freedom. The drawback is the time you waste going back and forth between two houses but it could be worse!
Option 6 (serial monogamist forever) is an option that many men find appealing. It's an option where there is a committed relationship but avoids the worst elements of Option 1 (Traditional Monogamous Marriage) and Option 2 (Serial Monogamous Marriage).
You are freshly out of a live in girlfriend option that didn't last permanently and you had a marriage end in the 2000s. Most relationships end and when they end, it's not a pleasant ending. Option 6 without living together limits the damage done at the end of relationships.
The most damaging endings to men occur when Option 1 ends and Option 2 ends, especially with children.
Most never married men who are 30+ have a male friend or acquaintance who has had an Option 1 or Option 2 type marriage end. I've already seen this with a few people I know and am likely to see more of this in the next 10 years among my friends and social connections. Almost all my male friends and acquaintances over the years have chosen the Traditional Monogamous Marriage path and many have had kids in their Traditional Monogamous Marriage, putting themselves at great risk in the future or having had already experienced a divorce with children involved. Even a childless divorce is an unpleasant ending. You know from your experience in the 2000s that it is likely to have a monogamous marriage end at some point in the future prior to one person dying.
Even when a Traditional Monogamous Marriage doesn't end, there's a good chance that it isn't a quality relationship and at least one partner has an affair at some point. It would be challenging for a man who values his masculinity to stay in a marriage after his wife has an affair. Plenty of beta males who get criticized on this forum constantly decide to leave marriages when it is discovered that their wives have affairs.
Yes, you're correct that a man will retain some freedom in an unmarried, serial monogamous relationship when he doesn't live with his girlfriend.
Two homeowners dating each other is more difficult to manage in an LTR but is more common in committed relationship when both partners are 30+. When the two partners live apart, some of the challenges of two homeowner relationships are lessened. When two homeowners form a relationships in their 30s and beyond, merging households becomes difficult in serious relationships. One of the homeowners often ends up selling. It's possible for one homeowner to use the house as a rental. One partner turning into a landlord while married or living with a romantic partner creates some challenges.
A lot of women end up as homeowners prior to marriage because they are uncomfortable with being lifelong renters for a variety of reasons. One common reason is that Millennial women have had extremely high pet ownership rates and certain dog breeds are not good fits for apartments. This leads Millennial women into either renting a single family house with a backyard (typically a shorter term solution of 2-4 years) or buying a house. At age 46, older Millennials women are likely a good part of your target market, since older Millennials are 35-41 years old now right now. It's important to understand how these women have typically been living their lives up to this point.
In a serial monogamous relationship model, most of these relationships will fail when the woman realizes that you have no intention of getting married or living with her. The relationships will typically fail around the 2-3 year point. You might be able to get 5 years out of this type of relationship with a strong frame (Iron Rule of Tomassi #1 -- Frame is Everything). Not living together enhances a frame. Even with a good frame, very few women will agree to an LTR that extends more than 2-5 years without living together and/or getting legally married. That's a combination of social conditioning and a biological desire to secure commitment. The women who are more inclined to stay in this type of relationship longer are more likely to be career-oriented women, typically 35+ and childless in many cases. It's difficult to even imagine a career-oriented older Millennial childless woman being in this type of relationship for more than 5 years.
Your frame of not wanting to live with future girlfriends is more likely to attract career-oriented women, similar to your most recent ex-girlfriend. The difference in the future as compared to your present/recent events is that the uncoupling will be less complicated.
With the unmarried serial monogamist path and the likelihood that you will be dating women 35+ in the future, it's likely that you'll be dating career-oriented women, especially if you choose childless women. If you want to avoid career-oriented women, you're likely ending up with some single mom with an unspectacular job of some kind.
You have some interesting choices to make in the near future and I expect that the information in the post can help guide those choices.