Well... this is why I don't do 'relationships'. I do know that most men want this. I don't have any real advice for men that are looking for long term committed relationships because I honestly don't know how to do this.
But when I look around at couples that seem to make this work the common factor is the woman in that relationship is WAY below the SMV of the man. So I guess if this is REALLY what a man WANTS, he needs to lower his standards and keep busting his @ss. But even if the dude is a 9 and the chick is a 7, there will be a line of dudes waiting to tap that. All she has to do is go on Bumble, and she'll have a 1,000 dudes hitting on her.
Lower your standards, then HOPE that she has the personality disposition to remain loyal until she hits the wall, because you can not control her. At that point it is all luck.
I know this is depressing, it is also not fair, it is not what men want to hear, but it is reality.