Sue, it is not an easy thing for people with anxiety to be assertive, especially when dealing with family. It's something I'm still struggling with, myself. But, I do believe if you practice being assertive, it will get easier. My suggestion is to start in small ways, with people that you feel comfortable with.By using whatever skills you have learned, and with practice and time, you can work up to more troublesome issues such as what you mentioned. Remember assertive behaviour is something that needs to be learned and practiced along with all the other skills. I hope this helped in some way.