Hetero o bicurioso?

Hello, why if I have my sexual preference well defined do I get so excited seeing testicles and cocks especially if they're flaccid?, I clarify I don't like men nor can I even see two men kissing but when it comes to touching, watching porn and seeing a flaccid cock or a guy with big balls excites me too much, lately the idea of a threesome with my wife has gotten into my head, especially the idea of being bisexual and enjoying with her a black man, just having oral sex and I get thrilled at the thought of sucking a cock and some rich balls. Before getting married and when I was a virgin I used to like exchanging photos with other men but that's as far as it went, I'd want to rub against another cock and feel an explosion of cum but I couldn't find anyone who wanted to and wasn't sure about the idea one day an older guy sucked me off in public transportation and it was a crazy experience however I didn't like men and still preferred women, I left those bisexual thoughts for a while but now they've come back, do you think I should experiment? what do you guys think is bad to have that thrill? is it normal? Here are some photos of what excites me



















Things I'd like to do when I get excited about it.