Thanks for posting your query.
status of an individual and the safety of having a life partner like that are not dependent on each other.
If the XXY
male is HIV positive and you wish to have him as your life partner and indulge in sexual activity, then you will mostly seroconvert to HIV positive state.
Coming to your second query:
The instances, where a person detected to be HIV positive and later turning on to be HIV negative, is rare.
He can get into marital relation but please confirm his HIV status again. In addition, his partner should be able to accept him as he is.
Hope this helps.