This is not uncommon. Some LGBT+ partners initially tell their Straight Partners that they are bisexual because they are still working through their own feelings and desires during their coming out process. It may take time for them to achieve clarity and acceptance around their own homosexuality. Unfortunately, some lesbian and gay individuals may initially come out as bisexual to their Straight Partners as a way to “soften the blow” of disclosure, or to mitigate a sense of guilt, without realizing this adds to the Straight Partner’s confusion and sense of betrayal if the relationship ultimately ends. The Straight Partner may hold out false hope that the relationship is salvageable if they believe their partner is truly bisexual, when in fact, their partner is gay or lesbian. 

While the labels and orientations are still in question, focus instead on the behavior of your LGBT+ partner. Are they keeping you informed of their own process? Are they engaging in constructive, honest communication around their feelings and desires? Are they listening to and respecting your thoughts and feelings as the Straight Partner, and as an equal partner in the relationship?  Are they maintaining an emotional or physical relationship with a person of their same sex?  Are they providing additional information to family members and friends?

If they are, that’s useful information. If they aren’t, that’s also useful information.