Thanks everyone for all the responses - lots of food for thought.
To everyone who has given great advice on the financial security side of things on this thread - at the moment I'm not too worried about that. I'm financially independent from my DP and have my own house. Obviously things would be different if we bought a house together, or had a child.
In response to a few questions - EllieQ - Why did you decide to TTC before you were married, despite wanting to get married - did you think your DP was going to change his mind? because we have fertility issues, and decided that we don't really have the luxury of time on our side any more - so best to crack on with it and TTC because it might take us some time.
Someone asked does my DP want to get married, or am I just his 'will do for now' girlfriend - He is definitely committed to me, and we are very much in love. But he always fobs me off with "Of course I want to marry you, just haven't really thought about it... no rush" etc.
So, after pondering this thread, I raised the issue with DP. He agreed that he is a little commitment phobic after his experiences, and I admitted that having lived with the world's worst commitment phobe, that I am damaged by that and need some assurance from him.
We both realized that we are punishing each other for the hurt we have both experienced (he's afraid to commit because of what his ex did to him, I'm afraid of non-commitment because of what mine did to me)
We both feel jaded about marriage because of what we have witnessed happening to other people recently, and we do wonder what is the point of going through that for a piece of paper... but we both agree that what we have is more special than what those unhappy marriages have.
I did point out that while we think that our relationship is happier / or as happy as anyone else we know we are the only couple we know that have made no commitment to each other none at all
I also pointed out to him that once in his life, he made a promise to love and cherish someone - and that someone was Not Me - and that makes me feel second best, even though he is way happier with me than he ever was with his ex. I think the balance needs to be redressed so that the biggest promises he's ever made in his life are to me, not someone else from the past.
I also had a mini 'feel sorry for myself moment' when I said that although he has gone through all that with someone else - I never have. No one has ever given me a ring. No one has ever proposed to me, and No one has ever promised themselves to me.
and that alone should be enough to persuade him that it's worth it for me.
So I guess this has turned into a 'Help me persuade my DP to propose to me' thread - but it has been a healthy discussion of the practical and emotional reasons to get married.
I still wonder 'what is the point' but I think I need to make it personal to me and DP and think that, for us, the act of making a commitment to each other and celebrating our love for each other is enough of a reason.
We ended the conversation with DP promising me that he wants to marry me, and will ask me soon. I definitely do not want to ask him - for the reasons I stated above. I told him that, sadly because of the scars I bear from my commitment phobic ex - it does hang over me and I would feel a whole lot happier and more secure if he did ask me sooner rather than later. He says he will.............. so I'll just have to wait and see.