Hi jennypennykenny,
Your situation sounds remarkably similar to mine. Except I don't have children and I have a very supportive mother, who couldn't stand to see me so depressed and unhappy.
I was married at 22 and I am now almost 30 and I've recently separated from my husband for the third time. I tried for seven years of counselling, talking to him, compromising, travelling together, etc, etc.
Your situation is slightly more complicated because you have children to consider. Ultimately if you want to be there, in that life and can accept the odd family trip to quieten that travel bug, then you need to try to work through those issues with your husband.
I did try, but I always had that nagging voice and I couldn't shake it.
I do believe the idea of travelling is more than just escaping the drudgery of everyday life and responsibilities. Personally, it has a lot to do with being independent and proving to myself that the world is not as small as it sometimes feels. Also showing people that I am courageous and strong and not just like everybody else, accepting the role of marriage and mother so easily.
For me, I've realised that marriage and children is definitely not what I want. I'm actually starting to despise listening to people talk about their weddings and their children. For some people, that is what they want in life. I now realise that I don't.
Perhaps you are experiencing a similar awakening. I think women are often pushed into this idea that a perfect partner and marriage is the answer to everything. But there has to be the right time and the right person.
Sorry for babbling but as I said, I'm going through a very similar situation at the moment. Keep going to see your therapist (I still am), talk through your thoughts and you will soon hear yourself and your heart.
I am planning on taking a year off work in 2012, travelling and working in Europe all by myself. And I can't wait!
Good luck.