Have you tried sexy underwear, or anything else that used to turn you DH on? I assume you have; but could the problem basically be that what you always has done, have become a little boring? Perhaps you need to try something new.
Seven years isn't a big age gap, but your DH may suddenly be feeling old and undesirable and can't get round to telling you so. I felt like that for most of the year following my sister's death and didn't really want sex, but kept on for my husband's sake. Now, happily, I want him and sex again, so perhaps it will come right for you and your DH too. In that particular case, it saved the marriage, but finally my friend got tired of being the other woman and broke off the relationship.
Right now you must be feeling pretty frustrated, so a vibrator might help, but it is not going to solve the basic problem: why your DH no longer wants sex.
It sounds to me, as if he does not know what is wrong himself, and until he does know, he can't tell you what the matter is either. A lot of people shrink from discussing sex with others - and the thought of talking to someone outside the relationship can be very off-putting.
Be patient a little longer, then if things don't right themselves, perhaps you should consider whether you and your husband could live with you having a lover? I know it isn't morally the best choice, but as you don't want to leave your husband, it might be worth considering very, very seriously, as obviously, it could be a potentially very difficult situation, if you do choose to go down that path.
I had a good friend who was the mistress of a married man whose wife, due to illness, was no longer able or willing, I don't know which, to have sex. She knew and had suggested to her husband that he should find an "accommodating" friend.