Been in a relationship for a year and 4 months but I feel like I may be gay / trans, help?

So I've been dating this girl for a year and 4 months, she lives with me apart from on weekends. For the past 3 or so years I've always thought of myself as bi-sexual, however at the moment I can't figure anything out in terms of what I actually am - could it be that I am bi-sexual and just wanting something different, or is it that I'm actually gay / trans?And if it's that I am gay / trans, I have no clue how I'd go about ending the relationship.Any help/advice would be massively appreciated :) Cheers