Unlike a controlling relationship, a loving relationship is where both parties in the relationship want to see eachother fly, they want to see eachother excel and be the best they can be, they want to help eachother achieve their goals and there is no competition, both are totally secure in themselves and are not threatened by the success of their partner.
However, in a relationship where one person exercises control over the other person, there is the exact opposite to this. In a controlling relationship, one partner seeks to dominate and make the other person subject to them and this is usually birthed out of insecurity. People that are insecure only feel like they are worth something when they put other people down, they can stand to see others excel, they can't stand to see others achieve, they cant stand to see others dreams and aspire and therefore they seek to put down and destroy rather than build the confidence and self esteem of their partner.
In most cases in a controlling relationship, it is the guy that usually has the tendency to want to control - this usually sterns from the whole "The man is the head of the home thing" When God says that the man is the head of the home, it doesn't mean that he is supposed to control the woman and force her to do things that she doesn't want to do. In fact, being the head means that you are the one responsible for her well being, you are responsible for her growth to make sure that she fulfils her destiny, you are responsible for loving her and making her shine so that she can rise to the top and be the best, that's what it truly means to be the head.
Controlling relationship is characterised by one partner trying to dominate the other and force the other person to be subject to their will. But God never intended for us to dominate one another, Gods intention was that we would dominate the resources of the earth not or human being - in fact, in Genesis 1: 26 God defines the boundaries of the dominion he gave us. That dominion was to be exercised over fishes of the sea, fowl of the air, cattle, the earth, and over every creeping thing that creeps upon the earth and another human being doesn't fall into that category.
God hates controlling relationships so much that he was upset when the Israelites insisted that Samuel should give them a king to rule over them, God was upset about this because he never intend for one human being to control another.
If you are in a controlling relationship you need to realise that it is not healthy for you. Nobody has the right to control your life, nobody has the right to force you to do things against your will, nobody has the right to tell you what you can or cant do or where you can or cant go. Out of love submission, you might decide that you want to willingly submit your will to theirs and that is okay as long as it is a decision you made or an agreement you both came to out of love, but if you are being bullied or beaten or manipulated into submission then that is wrong and out of order on the part of the partner that is doing that.
In a controlling relationship the controller uses manipulation or threats to get the other person to submit, so they stop giving affection as a way of control, or they make threats as a way of control. The controller needs to feel like they are in charge because without that sense of being in charge they don't feel like they have value or respect. While there is nothing wrong with wanting to be value and respected, there is a right and a wrong way to get that value and respect and bullying, abusing and putting your partner down to get it isn't the way you go, in fact the only thing you get when you do that is that they end up fearing you and where there is true love there shouldn't be fear because perfect love casts out fear (1 John 4:18), I should be able to be myself around you, I should be free around, I should be able to be vulnerable around you, I should have to be in fear of the one I supposedly love.
If you are in a controlling relationship, you need to ask yourself whether you want to live the rest of your life with someone who is hell bent on having dominion over you, who wants to control your life and monitor your every move, who wants to tell you what to do and how to be and how to dress and where you can and can't go, is that how you really want to live? Don't you think that is slavery? You were born to be free not to be a slave or subservient to anyone. If your excuse is that you love them, then I have to ask the question: is this really love? How can you say you love me when you are trying to dominate and control me? You won't allow me to be me? You are threatened by my achievements, you put me down and you claim to love me! That's not love.
Your life is too precious to live it in fear, your life is to precious for you to feel caged and enslaved and dominated by someone else, you deserve to be in a relationship where you will be free to be yourself, where you are free to contribute, where you are seen as an equal partner, where you can voice your ideas and opinion and it will be taken on board, where you are given the freedom to be you and do you and being you is celebrated not them trying to force you to be something else to feed their insecurity.
Let the controlling partner know that their controlling behaviour will no longer be tolerated, because as long as you tolerate it, you cant complain about it, and as long as you tolerate it, their controlling behaviour will continue. If they refuse to change, it might be in your best interest to exit the relationship (if you guys are not married that is, marriage is for better or worse so you will have to find other ways to get them to stop being so controlling i.e. counselling). The worst thing you can do is go into a marriage with someone who is controlling, if they are already controlling you in courtship, you will literally be their slave in marriage.
You should never tolerate a controlling relationship, you deserve to be free and happy.