I agree that you should try counselling first. There must be more to the situation than just sex/porn. There are many relationships that are successful without the couple having sex.

Perhaps your husband needs to come to grips that sex isn't the only important part of a relationship, that even if you "are boring" in bed, doesn't translate into not loving anymore. Lots of men equate having sex to being loved, whereas women can feel loved without having sex. It's a balance that both of you have to find.

Most people will say that 25 years of marriage is too much to give up because of a little porn or not enough (good) sex.