Need advice.

Hey guys, I don't know what to do.I'm in a long term relationship with the greatest girl ever and I love her to death. But ever since around freshman year of highschool (I'm now 21) I've been having homosexual tendencies and fantasies (I only watch gay porn, play with toys, and fantasize about my guy friends more than women). I figured the tendencies would go away but they just grew over time and I'm honestly so confused. I don't want to break up with my girlfriend because I love her and she's my best friend so I don't want to lose her, but I also really want to experiment with another guy. What should I do?Ps were both catholic and this kinda thing isn't the most excepted behavior with her and my family.