Hiya people

I am trying to figure out and make a decision on how to handle a situation i am currently in and i would like your opinion!

So..3 months ago i started dancing classes.. and there i noticed one woman who caught my attention, only to find out the day after that she has a boyfriend.. So i left it there and didnt approach her.

2 months later she starts to behave very differently towards me and i am trying to figure out how to respond..

- Her body language changed a lot and she is very receptive
- Smiles a lot and lights up and she see's me
- Engages in deep conversations and asks questions about me or my life
- Very playful and a bit jealous (in a playful way) when i dance with someone else
- Seems to pay more attention to me when bf is around (others noticed this too)
- They dont seem to have a good chemistry (as i noticed) and they are together 8 months (She said they were friends before and then became a couple)

Now i am interested in this lady and i would like to try a relationship with her (only if she breaks up of course).
I do respond to her flirts and i try not to be carried away with her since i like her. So i play it loose and i do flirt with other women as well. I have her number but i never call her since i respect her and dont want to put her in trouble.

What would you do in my position? How do i respond to a situation like this?

info : She is 24 he is 26 im 29

Thanks in advance for your time and help!

Mike