I understand the "no touching" your child thing. I'm a mother I get it... But I get the feeling, that the problems is a little bit of your controlling issues? especially with your latest comment " "Its hard being looked upon as a father figure and not being able or capable of parenting" <--- that's about the true-est (!!) words I've heard lately "... I've been a step parent - and had a few arguments with both the mother and my partner about parenting. it wasn't until we all sat down and discussed what we all expected that it got easier.

I would suggest some counselling, it sounds from what you have said the relationship is good in other ways.... Maybe getting together with a counsellor will be able to bring a few more things to the surface.