Maybe just ask that until it's been a while longer she take a bit of a step back. She may not even realize it's an issue, or he may be telling her it's fine, no big deal, this is totally normal behaviour. and NO if you don't have kids it isn't common sense to think that her picking LO up is a big deal. It's a learning process for everyone. They need to learn their boundaries, and you need to give a little. If they can respect that it's moving too fast and you're not comfortable with it after you calmly and clearly explain why to BOTH of them, not just him... then cut them a little slack. If she still oversteps clearly set boundaries then I'd kick up a fuss. It's a hard place to be in being a potential step parent. You never know if you're moving too fast or too slow. So maybe she just needs a bit more guidance.