For the question in the first post here, no. I am not okay with someone suddenly changing their mind about something that major this far into a relationship as I am with my partner. If someone I was interested in but hadn't started a relationship with yet told me they were bi or queer or pan, fine, no issue. I'm not at a place in my life where I want a relationship with someone unsure of their orientation.
Experiment with toys? Fine, no issue. I've been slowly introducing him to BDSM and the gear for that anyway. Suddenly wanting to experiment with someone not my gender, when we've been in a monogamous relationship for years and have had many many conversations about whether either of us is curious about anything or lacking anything? I don't think so. I've dealt with someone who lied for an extended amount of time about that and then were unfaithful. I have no tolerance for that kind of shit anymore.
Your second post in this thread and definitely ALL of the ones in Ask a Gay Man are mostly very confusing to read...