Straight
Don't put so much value on what others think or believe. More than likely, they've already judged you anyways. With that, some... your friends are being genuine while the rest are being fake. Just care & give thought as to the kind of person you are.
The friends (if any) that would show up to help you move without even being asked.... those are the ones to focus on.
H, you're 38 years old. Not so old that you stop growing, that age comes, but old enough to see what truly pleases you and what is just trivial lust. What do you want? If you believe that spending your life with another man will bring you more happiness and fulfillment than being with a woman, than this is your path. Weed through the party boys and find someone with the same values and outlook that you have. Fuck societal norms and what others think.
Hey my dude, don't be so hard on yourself (or your sexuality). You values are going to change as you age, and sure, you might slow down a bit. There will be other guys who want the same as you do. You could always try dating women for a while and see how it feels.
I wouldn't hide who you are (being bi, etc) but leave out the 'super slut' part with new partners. Most modern adults know gay guys (or just guys) can be slutty, but I wouldn't advertise it.