Aquilla, your situation is not at all unexpected. God made us with certain desires. Some have stronger than others. And old business saying goes like this; if in doubt, don't. That will work for you more than you realize.
The relationship you are in now sounds like a nightmare getting ready to happen. I think it is only fair to the lady to let her know you are having doubts about a permament relationship. I know someone that married someone that sounds exactly like your lady that is very, very controlling. I can't imagine telling any adult who they can talk to where they can go,etc. but that seems to be the way some operate.
Everyone needs flesh and blood to touch and talk to on occassion. But the answer you are seeking I don't really have. Perhaps part of it, but not all.
I have been married longer than I have been single, and as we have gotten older we have both mellowed quite a bit. Many never thought our marriage would last. But neither of us is in any way controlling. We both had to learn to give and I had to learn to just keep my mouth shut on some opinions. I think when you live with someone for many, many years you know very well what will push their buttons.
I would hate to be single after being married for so long, but this advice I will give you free of charge;

marry someone you have a friendship with more than you have a strong lust for. As you get older the latter will wain and the former will be more important to you.