Condoms reduce transmission from males to females by 96% so great protection.
You need a western blot but because you have frequent unprotected sex, the timing is tough. The western blot will tell you about infections 3 months ago and backward. The 1.77 could definitely be a false positive but right now you are in such limbo with this. There is probably a 75% chance that this is a false positive or an early infection and the index value will be going up later.