Just need advice

Hi everyone, so this is my first ENM relationship and I just need guidance. I love my partner so much, I have always been monogamous or been in monogamous relationships. My partner has always wanted to be poly but was in monogamous relationships so I guess it was a bit difficult for her. Right now I’m struggling a bit because I fear I’ll lose her, at least that’s what my guts tell me but most importantly because I feel like there is a disconnect. I’m very happy that she gets to be herself, is it bad that I’m scared? For context- communication between us has been low, we don’t flirt with each other anymore and I know she’s seeing someone. She has mentioned that they have good sexual chemistry and are planning to meet up soon. I just feel some type of way but I don’t want to make it about me because I really do love her and I’m happy that she gets to be herself. So I guess the question is, am I wrong for feeling this way and what can I do to support her better?