Questioning is in a sense a sexual orientation, although it may also not be one, since someone who is questioning is, for whatever reason, unsure of what gender(s) they are attracted to, if any. It can also mean being unsure of whether one is asexual or sexual. Being questioning is developmentally typical in early adolescence, although most people assume they’re straight and sexual because it’s the “default” sexual orientation. Being “bi-curious” and similar things are forms of being questioning, but they are not really inclusive.
There is much stigma associated with being questioning. Most people assume that you must somehow know your sexual orienttion, but are either afraid of coming out (if you are presumed to be queer), or “it’s just a phase” (if you’re assumed to be straight). In my own case, I was told that I only identified as first lesbian, then pansexual, and finally as questioning, because I wanted to be different in a way other than blindness.
I want to make this really clear: it’s okay to be questioning. It doesn’t even mean you’ll ever find otu your sexual orientation – you may not. If you do ever find out your sexual orientation, it doesn’t mean that you were “faking” when you were questioning. Being questioning also doesn’t mean that, if you’re in a relationship, you do not love your partner. Sexual orientation, after all, has to do with what gender(s) you are generally attracted to, rather than the gender of your current partner – which may not have been relevant in why you fell in love with them.
I identify as questioning. I am aware that I possess some straight privilege due to being in an opposite-sex relationship, but I do encounter a lot of the stigma I described above when trying to come out as questioning. I have internalized some of this, but I am learning that, as I said, it’s totally fine not to know your sexual orientation.