I normally just read. But I'm shocked by so many of the responses.
There are so many judgy responses on both sides of the equation, and I feel as though I'm about to add to them.
What I've read on here is that the OP has more than one child. That she and her DH had decided upon a set amount and according to the OP he has been stringing her along and changed his mind. 7 long years. Now I don't know anything about their relationship, but it seems there is a communication problem, if he has changed his mind and felt he couldn't let her know that then the marriage has issues, long before further children come along, OP may want to deal with that.
Equally, and I suspect this is more likely, it could simply be that he thought he would want more children, living with children change his mind, but he thought that feeling was temporary but has realised that he really doesn't want to go back to those early stages.
For all we know he could be worried about not being able to spend enough time with the existing children, wife, himself if they go for another one. Or even having enough money, some people do worry about the practicalities. The OP should probably try communicating with her DH to get to the bottom of his concerns if there are any.
It's all very well saying the OP feels betrayed, cheated etc but I suspect the whole situation is a lot more complex than just her side of the story she has chosen to share.
And lastly, this whole thing about leaving her DH. Really? What did we all do marry sperm donors? I don't know about the rest of you I married my DH. There are a lot of things I may have wanted to do, but life gets in the way and doesn't happen - sometimes his unadventurous spirit gets in the way - but I didn't marry the prospect of adventure, I married him. If Divorce is the go to response to troubles in marriage, I humbly suggest getting married probably isn't for you. And if you are already married, oh well and good luck.