I'm going to be honest, my patience for this part of the forum has worn very thin over the years for a few reasons, but mainly for people throwing out comments or looking to start a fight.
Stop it.
You're (mostly) adults, start acting like it.
Now, back to the comic and the most likely reason why Faye is upset. Consider this - this isn't about Faye's relationship with Bubbles, this is about Faye's personal view of herself. Look at yesterday's comic when she said ""Hah! I never thought about datin' a robot or a lady 'afore I met Bubs."
You have this moment where Faye admits that her entire sexual identity has changed, and that maybe the real her had been allowed to flourish and grow thanks to Bubbles, heavily implying that its a true love. And immediately, Bubbles comments that due to her memory wipe, she can't remember if she was in a relationship before. And suddenly Faye is faced with a couple of prospects:
1 - The prospect that Bubbles was in a relationship before her and that everything about their relationship wasn't built on the truth (not a lie, Bubbles was almost in a state of tabula rasa, if she can't remember, she can't lie).
2 - The prospect of there could be at least one spectre amongst the ghosts of Bubble's past having loved her. Its a lost love situation. Sure, there's love for their current partner, but there's always that undercurrent that in their heart there's someone else. An ex is always easier to deal with, the dead not so much, as they become idealised. Even if Bubbles can't remember her past, to Faye there's suddenly this ghost looming over them, made worse by the fact that Bubbles can't remember them.
3 - The prospect that she isn't Bubbles' first and that Bubbles may have been the key for others in the past. Immediately that takes away some of the sheen from the relationship, perhaps tainting it in some way.
One second Faye's relationship with Bubbles is going great and literally a second later, Faye has gotten smacked in the face by a past that neither she nor Bubbles can achieve closure with. This is more than the realisation that Bubbles had a past, this is realising that Bubbles had a past with people, people she loved, people who may have meant more. And that is a lot to take in in a matter of seconds. Is Faye acting in an irrational manner? Yeah, but then again her entire world has just been upended, everything she was certain about with her relationship with Bubbles is now no longer certain. And previous experience has shown us that Faye can't handle sudden changes in a healthy manner, she acts out and as for what happens next, well, tomorrow is Friday, perfect day for a cliffhanger. That's all I'm saying.