ANSWER - I agree with your point that while there is a marriage bond he has a link that he can use to manipulate you. However without fuller details I am not sure how you are planning to use your own blood for an unbinding. I get the sense that you want to use the power of blood in a spell but you are unsure what would be achieved by this practically.
The way I could see it working is if you could obtain both your blood and his blood and then work a spell around gradual dilution of the mixture until the water runs clear and your bond is washed away. Something like this would be very powerful. Using just your own blood seems a bit random and I don’t think your spell will be an effective one unless you are very clear in your own mind about why you are using blood, what specific purpose it plays in the spell and what outcome you intend to achieve with it.
My preference for unbinding spells is a very physical depiction of a break. Have you perhaps a vase or something similarly breakable given to you as a wedding present? A spell worked around the finale of smashing that would be suitable for your circumstances (as well as enormously satisfying, lol).
My best suggestion for you is that you use something to replicate the “whole” of your union and then work your spell around the separation of the whole into two halves. I like the idea of baking a loaf of bread for this purpose as while you are kneading it you can really focus your energies into it and make it a strong symbol of your marriage. If you have any of his toenails, hair clippings etc you can add them to one half of the loaf before baking and on the other half you can add something similar (or blood if you prefer) belonging to you. If you do not have anything personal of his then write his name on rice paper and bury it into his half of the loaf.
Once the loaf is baked construct your ritual around the breaking of the bread. I would then suggest that you take his half, crumble it and sprinkle the crumbs in several different locations so the parts are disparate and cannot combine to reform the whole. (I know a few witches who would extend this spell to consuming his half of the loaf so as to symbolise a conquest over him. I will leave that to your own discretion.)
That’s just what I’d do, you might come up with something different or better. You may even find a good reason for using the blood. What I will say to you though is if you are putting together a ritual make sure you understand the purpose and the symbolism of every part of it. Don’t just use something because it has inherent power, understand the specific role it is playing in your working. If you do that you can’t go far wrong!