Welcome to the Forum. I'll be pleased to comment. Indeterminate HIV tests can be very disconcerting however in reading your post, I note that since your indeterminate test at 31 days, your negative Western Blot, as well subsequent negative 4th generation/DUO tests supercede your indeterminate test. You do you have HIV from the exposure that you reference.
In answer to your specific questions:
1.- Can I consider the negative results conclusive?
Yes, you should. Your negative tests should be considered conclusive.
2.- Do I have to retest at 12 weeks?
No, there is no need for further testing.
3.- Can I have unprotected sex with my husband without the fear of spreading HIV.
Yes, with negative tests you need not worry about transmitting HIV to your husband.
4.- What can be the reason for the sliglty positive results?
The origins of false positive results are not well known. They are uncommon and when they occur probably have many causes.
5.- Should I be worried to have again a false positive result? Does false postive happen very often?
Some people, again, for unknown reasons, have repeated false positive results. Given that your tests since the indeterminate were negative, chances are that you will not have further false positive results.
I hope these comments are helpful. EWH
Thanks for your answer. I imagine that when you say "You do you have HIV from the exposure that you reference" you mean "You do not have HIV from the exposure that you reference." Thanks for clarify it.
You are talking about testing at certain dates, i.e. "33 days after exposure", etc. This is what I referrred to. I know nothing about your exposure and, in this case, probably do not need to. EWH
I am just saying that the there is a mistake in last sentence of your first paragraph when you write " ... YOU DO YOU HAVE HIV ..."
You are correct. Sorry for the type. You do NOT have HIV. EWH