This is essentially how I came out when I was 19 years old. I was engaged to the guy you described- who I'll call "T". He knew I'd always had feelings for women. But he loved me and I thought he was going to take care of me - and that was the glue that held us together. Then he got into drinking heavily, doing hallucinigenic drugs and smoking pot. He was neglecting me emotionally and phsyically. The relationship got to be messy and I jumped ship to be with a wonderful woman I'd met at work- "D".
Suddenly I felt free. That's the best way I can describe it. She was the catalyst for my taking hold of a life I was destined to live. A life I understood. Things made sense- I felt whole. Making the choice to come out felt like the most loving, honorable thing I could have done for myself. It's so hard to put into words.
Together, "D" and I made some huge leaps and life changes in a short time, as we both had big common goals. I will tell you we didn't last. A relationship with this kind of intense rescuee/rescuer foundation can't last. (However, we're still good friends, after all these years.) BUT my life is amazing in ways it never would have been had I remained trapped in the life that wasn't meant for me.
When I was with "T," I had no visions, no dreams, no goals. I understand now that I was depressed. But my life seemed 2 demensional. I felt like I was walking around in a dream- or living someone else's life. I worked at a gas station and a direct care facility. I had no college degree and came from a working class family, so I figured this was my life. A dingy apt. in a big dingy city working high demand, low wage jobs in a co-cependant marriage for the rest of my life.
The day I came out, I felt a shift. I realize I was euphoric with infatuation- but it was more than that. I felt like I was waking from a dream- like my eyes were suddenly open to endless possibilities. I immediately started remembering life goals and dreams I had as a child. I woke up to my life.
12 years later, (I'm 32 years old), I'm in an amazing relationship and together we own (mortgage free- yippee!) a 26 acre farm on the top of a hill in New England, run a successful carpentry business, are artists, have horses (my childhood dream), and have many more common dreams to fullfill together. We have a good social life, laugh, play, work, and support eachother attentively and lovingly in times of crisis. We certainly aren't rich by any means and have to achieve our goals with good old fashioned "elbow grease" and perseverance, but we're financially stable and that's a first in my life. I KNOW I never would have acheived ANY of these things had I continued to try and ignore my true self.
I hope my story helps shed some light on your situation and makes you feel a little less alone. Honoring who you are is the kindest, most important thing you can do for yourself. You need to ask yourself some hard questions. Are you just looking for an easy out from a difficult relationship with your husband? Or are you truly not heterosexual and have been ignoring your sexuality for the past 42 years? Or are you just bored and need some excitement? What are you trying to escape- relationship troubles or a heterosexual lifestyle? I'll tell you frankly that a lesbian relationship has many more complications and difficult moments b/c of social remifications than a heterosexual one. So if it's relationship work you're afraid of, you'll be unpleasantly surprised. You're son is old enough that you could embark on a new life of your own. But your troubles will follow you if you don't deal with them. I don't mean this in a harsh way- just trying to offer some advise you were asking for. Good luck to you! I hope you can make things work for yourself.