Why can't I get over my SO's history?

A)

Or
B)

Save the money and time, avoid the former and take the latter.

A competant former may well have you try the latter.

I wonder if all those calling the OP a jerk are aware of how utterly uncontrollable jealousy can be? It’s a neurosis that you really can’t understand until it’s happened to you. I’ve had it and it drove me half insane. I admit it did make me act like a jerk at the time. But it went away of its own accord.

I’ve also been on the receiving end: I’m quite obsessed with all things east Asian. I once had a relationship with a Chinese girl.

For a long time, my girlfriend (now wife) irrationally conflated the two things, with unpleasant results.

Until I took her to east Asia, and got her obsessed too. Her growing trust in me helped, but the trips to Asia really sealed it.

So why not get into Spanish stuff and put your mind at rest?