Of your neg after 7 years you have no reason to worry, if your neg after 3 months exposure that is conclusive.
You can not pass HIV to your boyfriend if you don't have it.
Any test performed 3 months after a known exposure (unprotected sex) is considered definite to exclude HIV infection. As I understand, you had already several tests done after you ended with your husband. Plus, you always had protected sex with your husband, so you had no risk.
It seems your boyfriend has an HIV phobia, so it would be wise to take him to some HIV counselor who can talk to him about this and his irrational fears. If he can't believe in the counselor, you can both go and test together just to ease his fears.
Thanks fo much for the good news! I have passed it along to my boyfriend and it has greatly put his mind at ease. It really seems to make a difference when the news comes from someone else. I do really appreciate it.