Bisexual or “confused”

I recently came out to my mom about me being bisexual ( I’ve always said it but my family never takes me seriously 🙃). I’m currently in a 5 year relationship with a man. My mom told me I was whistling his time and that I’m confused and being selfish in terms of my relationship. That kinda hurt my feelings. I came out to my bf a couple months ago and he was very understanding of the topic and wasn’t ignorant about it. Am I confused bc I’ve been with him for so long? ( since going into high school) or am I waiting his time ? Am I not bisexual ? I’m lost 😞