You should never feel embarrassed or weak when telling anyone about your migraine. It's an illness that you have no control over. Perhaps it would help to write about your symptoms on a day that you are feeling well and give that to your partner. It's very hard for people to understand just how debilitating migraine can be. Educating yourself and your partner is probably the best way for him to understand and for you to come to accept what migraine really is.
Keep posting and reading on this site, there are many people here who understand and empathize with you.