Not getting married. Finding a woman (or series of women) willing to be an unmarried girlfriend, and NOT intermingling finances.
As far as housing, either maintaining separate residences, or the guy moving into the woman's house. While together, he may contribute his share of the living expenses, but if the relationship ends, then he moves out. She keeps the house, but his financial support immediately ceases and she pays her own bills at that point.
That’s called staying a bachelor. Its not new. :-)
I know someone who had a 97 page prenup. LOL Funny to read. It even spelled out who paid to get the drive-way plowed. They apparently didn’t trust one another enough to have a small joint checking account to cover such expenses. He pre-deceased her but until the day he died he never told her who he was leaving his estate to.
You guys! LOL