Look, you're pushing WAY TOO HARD, ESPECIALLY if she is not part of the discussion. I would do NONE of what you have been doing without an OK from her. You stand a real high chance of weirding her out, pushing her away until she eventually leaves and possibly tells everyone else about how "weird" you were!
Communication is everything in good relationship and you seem to be avoiding it out of fear of not getting the answer that YOU want. WHAT ABOUT HER!?
When my wife and I were dating she was well aware of my fascination of wearing and using diapers but still, she was spoken to about everything before I ever considered wearing with her there. Sure I wish I could have done more with her, but don't be GREEDY! My GF/WIFE was perfectly OK with my wearing OCCASIONALLY, when we were alone and we had sex with me wearing thousands of times. Some of the rules I never pushed were no messing with here around, no trying to force her to wear (she did, but she volunteered the very few times she did so), NEVER wearing when we were going anywhere outside of going for a hike or going fishing with just the two of us.
You need to sit down and frankly discuss this and BE HONEST! How can you know what she might say or do without doing this? To just do what you have been doing without input from her is playing with fire and if not careful, you're likely to get burned!!!. I know these discussions are difficult and I realize she might be 100% opposed to you wearing at all but IF you insist on diapers being a part of who you are, you're doing both of you a favor learning this now so she can find who she is looking for and you can find someone more open to what you're doing. Just be aware that the majority of women are NOT going to look kindly upon this activity as it is badly misunderstood and being you already have someone who is at least slightly open to you wearing, be satisfied and not greedy! So what if you can't wear to bed. So what if you have to wear when she is not around. Not ideal (in your mind) but far better than one who goes around telling everyone she meets about how her boyfriend likes to wear/use diapers, onesies, act like a baby etc.
This is of course just my opinion, but I feel this is accurate and wise advice.
CptKirk