Fivedogsrule, that's a great update! And I have a wonderful piece of news for you -- NO water you are ever going to dive in is as corrosive to the nose as a public, chorinated swimming pool is. In fact, ocean water isn't bad at all, on the nose or the eyes (although it can be darned cold). If you can swim around for an entire evening in the pool without a mask, I think your nose-breathing issues sound pretty solved!
I'm glad your instructors gave you the space and time to get comfortable. This is one of the big problems with a lot of classes . . . the schedule is tight, and people are pushed to get through things before they've had a chance to process them the way they need to, to feel confident. Thing sound so much better now.
And don't allow yourself to feel you are holding your BF back. If he's the more natural diver, he HAS to be patient with you. And if he's not -- find somebody else to dive with! As I think I may have mentioned, I didn't dive with my husband for almost six months after we got certified (except during travel, when I had to, and that led to quarrels). He wouldn't respect my nervousness and I couldn't cope with his behavior, so it was better for us to dive with different partners. Over time, I got better and he accepted some constraints, and nowadays, we dive together just fine -- but it was an evolution. And you have to believe that you have the right to insist on diving in a way that makes YOU comfortable.