No, it doesn't entitle her to keep interfering and trying to control you, especially now that you're an adult and also married. It's no accident the Bible says part of God's pattern for marriage is that "a man leaves his father and mother and is united to his wife" (Genesis 2:24).
At the same time, I hope you'll try to see things through your mother's eyes, as best you can. No doubt she feels all alone; her husband has passed away, and now you're no longer part of her life (at least like you once were). I can't help but wonder if her attempts to interfere are actually driven by loneliness, or at least by a feeling on her part that life has lost its meaning. I may be wrong, but you might think about it.
Situations like this can be difficult to resolve, but let me make three brief suggestions. First, take the initiative to keep in touch with your mother. Elsewhere, you complain about how often she calls you, but do you ever call to find out what's happening in her life? Over time, it might keep her from prying so much into your life.
Then gently but firmly remind her that while you love her and value her, you and your husband have your own family now, and you hope she'll respect that. In addition, pray for her, and urge her to put her hope in Christ -- and also become more active in her church.