I think the best time for romance is until the end, it has an emotional strength, it gives you strength, hope and many other stuff, i would not like to do it after, from my point of view if you finish the game the romance should not be an option, like side-quests if you don't do them on lets say Peak 15, you can't return later to do it, the same thing should apply to romance.
The romance evolves based on more then talking with the character you wan't to romance, what happends in some missions are important parts like the trust you place in Liara when you take her with you to find her mother... It makes the romance more complex.
I respectfully disagree with that opinion. It actually makes the most sense role-playing wise to wait until the end. Throughout the story Shepard is constantly being reminded how high stakes the mission is especially with characters referring to it as a “suicide mission.” You’d expect a career special forces soldier like Shepard to be professional enough to put their feelings aside until after the mission.
This also reminds me of a boxing superstition that some boxers still follow today about not having sex when they have a fight coming up because it makes your legs weak😂
