Re (from PolyCurious4, Post #6):
"There have been other areas that Hubby had concerns about as well but because we had such a good connection I was willing to go with the flow ... There have been the issues that when trying to schedule it felt like at their whim."
It sounds like you'll eventually need to discuss some of your other concerns with them. Maybe you don't need them to do things totally your way, but you still need them to negotiate some kind of middle ground with you, where there is give and take on both sides.
I think it's a good idea to have some "platonic date nights," so you can develop that part of the relationship (which is important to you). Are you also feeling that the one (maybe two) nights a week just isn't satisfying you as far as a relationship is concerned? Maybe something can be worked out where you always get together twice a week, once for "platonic relations," and once for "romantic relations." It depends on what they're willing to do, but you'll probably have to be the one to bring it up with them; they probably won't bring it up.
It seems to me that it's not so much a matter of how long a relationship should be given to develop, as much as it is getting what you need from this specific relationship, and coming up with a compromise that all four of you can live with.
I hope you all get a good chance to work things out.