I've gone back and forth on this one a few times myself. I think that if I were to have the editorial power to do I would simply do this. Have one title where adventures take pace in what is the traditional scenario with the love triangle and then have another book that's meant to be farther in the future where Supermans life has changed a bit and Lois and Superman are married. This is comics. Not even the sky is the limit so why not have both?
I don't understand why it has to be sort of an either/or thing unless you're coming from the standpoint that Superman must be like a monk or something. Which while I understand that he must forever walk a line between human and Kryptonian, something about the idea of him never being able to have a meaningful relationship with a woman just doesn't sit right with me. I feel his mission of truth and justice shouldn't be played as a curse with Kal-El as a lonely puppet of destiny. Even though I do like some of the aspects grand destiny in the movies.
Kinda reminds me of the stuff I've been finding out in regards to Doctor Who fandom where apparently there was some sort of mandate about the Doctor ever being potrayed as having romantic feeling or sexual attraction to one of his companions and based on this some fans are really upset that in the latest series that kind of connection is very obvious between he and current companion Rose Tyler.
I've never liked that angle re Superman, that he is destined for a life of miserable self-sacrifice. Pah!
There's a lot more life in him than that. He's much better as portrayed in the Bronze Age or on George Reeves' TV show... very smart and with a cheeky grin on occasion. Superman is enjoying his life and he loves helping people. It's not a depressing mission carried out by a morose outcast or whatever the current rubbish is.
I would fully expect Superman to get married one day and have a happy life with his wife. I don't have a problem with your alternate timeline idea to present the marriage, but that option has always been there and has been used very successfully -- Imaginary stories. "Imagine if Superman married Lois." That can be an Imaginary series, no sweat, set in "the not too distant future".