Is there anything wrong with that? 
I dont think its a matter of (dis)respect. Its just what you’re comfortable with.
I just dont see the big deal about tum/aap…every couple has what they’re comfortable with. i never call my husband by his name (and neither does he)…but I extend that to everyone 
Exactly. Sometimes Ill get mixed up. Its really not meant out of disrespect. One should realize if someone is being deliberately disrespectful vs just mixing it up..esp when ure in a conversation, you’re thinking more about the topic at hand, than trying to get the right term in.
Oh, in front of in-laws I dont talk to him. If I do its in English, so no aap/tum ka masla