Why is it so difficult for people to believe that a gay person can actually identify as gay yet at the same time have a healthy/happy relationship with a heterosexual partner?

I've been through a lot recently and I've dealing with serious anxiety issues, mainly focused on my sexuality. You see, I've known I'm gay since I was a teen and just about all of my sexual experiences and desires have been homosexual...well right up to a major disappointment and then I let myself live outside of the typical gay life. That was when I met my current wife of almost two decades...I fell in love with her, her gender was irrelevant.

Although she's known from the beginning of my past and my sexual preferences, I don't think she has truly accepted my sexuality and I've never truly stated outright that "I'm gay". My anxiety has caused memory issues and I feel that if I don't address the causes of the anxiety...well, I'm going to lose myself. So after all these years I've decided to "officially come out" and live more authentically. I don't mean changing how I live, I don't want my relationship to change...but hiding my sexuality, well I've done that for 30 years and enough is enough. And please believe me, I'm under no illusions that my life might/will change by coming out.

The thing that bothers me the most though, is that no matter who've I've talked to...gay/str8, married/single....they all seem to feel that I can't be gay and be in a relationship with a woman. It's like a the binary world of gay and straight, but if you aren't 100% homosexual or 100% heterosexual...you're bisexual. I know I hate labels, but identifying as bisexual doesn't describe me. I just say that I'm gay with a small slice of hetero, that slice being my wife.

I mean, seriously, how do I address my anxiety over being gay? Why can't I try and maintain my relationship as it is? I'm just as gay now as I was two decades ago when I met my wife. I married her as a gay man, I had kids as a gay man. Sure I wasn't publicly identifying as gay...but we both knew that part of me existed. Now I just need to remove that anxiety, and coming out is the only way I can see. Even if I use all my energy to hide it away, it'll always be there causing a pressure I can't take any more. I have to release it, before it takes too great a toll on me.

P.S. Yes I am seeing a therapist for the anxiety.