I said 1-2 years, but I likely could've said other. The first time it came up I'd been seeing my boyfriend for about 6 months, and he had a lot of performance issues with condoms. He wasn't having intercourse with anyone else, and was willing to use condoms if he started. In retrospect I realized I was rushing it. My (now ex) husband and I didn't come to a consensus on that before we broke up. We broke up because he'd had unprotected sex with somebody. I'm pretty sure I would not consider stopping condom use for at least a year into a new relationship at this point.
So I never assume if I meet somebody they are "trustworthy" as people make mistakes, and people break your trust (even ones you've known for a decade), and people sometimes trust people they shouldn't when they say they have negative test results. I don't want to base my sexual health decisions on something as uncertain as trust.
I use condoms for oral sex with new partners. For me considering removing that barrier happens around 6 months to a year. If somebody had a new partner every 3 months, I don't think I'd be fluid bonding at all. I'd rather be safe then sorry, and don't want to have to monitor new partners STI tests, or go back and forth between condoms or not every time somebody new is in the picture.
For PIV that it's likely that it'll always be condoms unless I end up in another primary type relationship, and/or I am spending time with everybody in the fluid bonded group. Say my partner's wife is having unprotected sex with a person I haven't met, that's one risk level too far for me to get involved with.
Happiness will never come to those who fail to appreciate what they already have.