There is an excellent thread here by someone with OCD who has experienced this and it actually LGBT+:
https://www.nomorepanic.co.uk/showth...ective-on-HOCD
I think you have to be careful with stories of people changing their sexual preferences after many years. It tends to be uncommon compared to those who knew what they always were. I suspect much is left out in these stories about the person always being a bit unsure or open to same sex relationships yet never exploring them.
However, you know this is about anxiety. You need to work on acceptance of this and who you know you are. The subconscious slipping in doubts is no different to it saying "are you sure you don't want to buy that more expensive item" just about an issue closer to your beliefs hence it causing you anxiety. But the subconscious is always popping out thoughts and we usually dismiss them as they are trivial e.g. do we need more milk when walking around the supermarket. The key is to react in a similar 'meh' manner so these thoughts don't bother you.