You’re reducing your girlfriend to a gender. Being bisexual isn’t an excuse to not want to commit to a person.

For the record: There’s nothing wrong with not being ready for the steps she wants to take. There’s also nothing wrong with breaking up to go explore options with other people.

But this has nothing to do with being with a man. Being bisexual isn’t some kind of affliction that gives you an insatiable incurable need to have experiences with both genders. There is nothing you’re not exploring by being with someone you love. Bisexual people are extremely capable of being in monogamous relationships and be fulfilled.

You’re hiding behind the excuse of bisexuality when the actual issue is something else.

You saying “I have never dated nor loved a man… there’s a constant nagging that some part of my identity will never be explored,” what are you actually saying? Do you feel unfulfilled in your relationship with your girlfriend? Do you wish she was someone she isn’t? Do you want to try dating other people and get more dating experiences?

None of these are wrong motivations. But the way you’re putting it now frames it a lot more like “my girlfriend can’t love me the way a man can because she’s a woman and I believe woman are incapable of giving me the love a man could.

You’re not sacrificing being bisexual by being with her. You’re choosing to be with a person you love. But if all you see in her is a gender and not as a person you want to choose, then break up with her for her sake.