The question was not about having unprotected sex. It was just about having sex. I wouldn't have sex with someone who was HIV+ unless I was deeply in love with them. Even so, safe sex would still be a requirement.
However, as Vic has pointed out, it would be difficult to allow myself to fall that deeply in love with them -- which is a separate topic completely. Honestly, I think the only way that would work is if I had gotten to know someone, found myself falling for them and THEN started dating them -- only to learn they were positive. If they didn't tell me early on in the dating process, I would feel... not betrayed, but like that they had difficulty being honest with me.