How to not fall in love again?

I HV been in love with a girl who has boyfriend. We talk often, shares to take care about messages, though we share close relation i feel feelings from my side only. She has not disclose her feeling to me openly and once she has said she has trust issue with anyone approaching her. Now it's been one month my feelings remain same. I don't want to hurt her or her relation with his bf. I just don't want to feeling love for her Alys. I want to move on by can't. How can i do it. Help please.