True Left

"learning to love someone that you were not initially attracted to can be a romantic undertaking as the only way to find something attractive about the arranged spouse would be for the other person to learn absolutely everything about them. "

This seems to be a form of adulteration. It reminds me of being forced to learn to play a musical instrument (that I had no interest in) by adults claiming I will learn to like it after I know it inside out. (In reality, it has only caused me to hate Western classical music.)

Romanticism celebrates love at first sight. This can occur within the setting of arranged meetings, just as it can occur when people meet each other by genuine coincidence (e.g. neighbours, colleagues, etc.). Where it cannot occur is when either person is trying to look for someone.

"I think the only way an arranged marriage between two noble persons could turn into a disaster is if both decide to dig in their heels and resist the arrangement purely on the grounds that it was an arranged match in the first place?"

Again, arranged does not mean compulsory. It simply means it can happen without either of the subjects taking any initiative:

https://trueleft.createaforum.com/issues/social-decolonization/msg12571/#msg12571

"the first thing most Westerners think about when it comes to romantic relationships is physical attraction and sexual intercourse."

The main problem is failure on the part of inferior people to distinguish genuine romantic love from mere lust. If you see someone and want to have sex with them, it is lust. If you see someone and want to prevent other people from having sex with them, it could be romantic love. There is a simple way to test what it really going on. You are given two choices:

a) You can have sex with that person, but so can others.
b) You can't have sex with that person, but neither can anyone else. 

Genuine romantic love will lead you to choose b) without hesitation.

"in an arranged marriage where two noble partners are not sexually attracted to each other, if sex is a must have for one of the people, or both, in the marriage they could seek it else where as long as they were honest and upfront about their intentions and reasoning with the other person in the arranged marriage?"

And as long as they admit they do not love each other. Because if they did, they would rather not have sex with others than hurt their spouse by doing so. Then, since they do not love each other, why marry each other? They should turn down the arranged marriage! Again, arranged does not mean compulsory.