Yes, a bisexual man can absolutely date a gay man. Sexual orientation doesn't determine who someone can date or have a relationship with. Bisexuality refers to being attracted to people of both genders, while being gay means being attracted exclusively to people of the same gender.
In this scenario, the bi guy and the gay guy could be in a relationship together, just like any other couple. The key to a successful relationship is communication, understanding, and mutual respect for each other's sexual orientation and feelings.
It's essential for both individuals to be open and honest about their preferences, boundaries, and expectations from the relationship. As long as there is a strong emotional connection, respect, and shared interests, the specific sexual orientations of the individuals involved should not be a barrier to a loving and fulfilling relationship.