The question is whether the boyfriend cohabits with her. If this is court ordered alimony and she cohabits it could terminate her alimony. It takes more than a few overnights. The boyfriend must actually assume marital type obligations such as helping pay bills, buying groceries, etc.
No attorney-client relationship is created by this response. Always see an attorney in person to create an attorney-client relationship. The author of this opinion is licensed only in the states of NC, SC and TN.
I agree with Mr. Kelso and to add this: NEVER cease these payments until you receive legal advice from an attorney you hire and/or you get an order from Court terminating your obligation to make payments.
Payment of alimony is by a court order. Until such time as that order is no longer in effect, one complies with their valid court order. If you believe there is evidence to have the order changed, retain counsel of your choice and present your case to the court.