Sounds just like it says - he wants to bind you two together forever. Putting the fact that you'd need to do more research on it aside, I'd recommend you don't do it. If you have to rely on magic to hold you two together, that doesn't sound great. Not to mention, if you two get sick of eachother or things don't work out, you might create more problems if you bind yourselves to each other or create that kind of obligation on the relationship. Also, there's the fact that anything involving blood is risky, both in a magical and medical sense; unless you have proof that any and all blood involved is clean from a doctor, you run the risk of exposing yourselves to blood transferrable diseases/illnesses.
Just enjoy the time you two have together, and work on creating a good, strong, and healthy relationship naturally.