Cindy's personality doesn't bother me but her obvious desperation to change her life where Ian can help the change but the attraction she feels for Axel is evident and if we add that to the consequences of being discovered by others, it seems like a route that I don't see a good ending, right?
Desperation comes from needs and Cindy needs to find her true self. She's doing her accounting job at her father's place which we know was given to her on a silver platter. She never worked hard for herself because she got everything without doing much work. Cindy's at that age when the realisation hits you hard, she has nothing to show for it. Hence she is trying to change, which is positive.
Personality is more important than having good looks. Sure, good looks will open up doors for potential partners much easier, but after that; good looks will not carry you throughout a relationship. Eh, Axel is a handsome bloke who wouldn't feel attracted to him? Again, the attraction is superficial, not emotional. Lena knows Axel's inner self and even tries to warn Cindy at the pub.
You can kiss Cindy and stop it then and there without getting caught by Ivy/Jeremy and still keep it on the down low. Going after your friend's SO is a shitty move nonetheless. Get ostracized by your group when things blow up or just cut ties with them before, it's up to you. These are the two scenarios that I see on Cindy's path. Ivy said it's a rumour and not a definite truth, so take that accusation about Cindy with a grain of salt.