If you have difficulty talking with her about this, then do write her a letter.
Be overly kind and complimentary. Rely heavily on your appreciation of the sacrifices she made in raising you. Then reveal you’re not sure that, in it’s current form, your relationship is healthy for either of you. It will breed conflict with your husband and you, and it’s time for her to open her life to other things than you. Tell her you want these things for her. Make it clear you are sending her this letter because attempts to discuss this with her seem to go off the tracks and end in bad feelings and that is not your goal. Tell her, this is a new time in your life, things are going to change, for you, and for her, by necessity. Then spell out your boundaries, clearly. You no longer need to speak daily, or feel the need for her approval of your every action, and that this is normal for grown adult children. Tell her outright her neediness is not going to shape your relationship, attempts to guilt you into things, personal attacks etc will have no room in your life. Tell her it’s time for you and her to move on to the next level, a more mature and healthy relationship. Finish up by telling her you love her and always will, but, as an adult, you have to take responsibility for the personal relationships in your life, even the one with your mother. Tell her how deeply you would regret having to step away from your relationship if she’s unable to accept your boundaries as outlined. Tell how confident you are that she can do this, if she tries, and how wonderful a future together you share if she can make the effort.
Then be prepared to hold the hard line. Remove yourself, get off the phone, withdraw, whenever she reverts to guilting, attacking, overt neediness as manipulation. Do not engage. A simple, “We talked about this, Mom.”, should do the trick, as you withdraw. But she’ll be like a spoiled child, I predict, she’ll try everything. But, if you hold firm to your position, (don’t get angry, don’t hold a grudge), she’ll settle in to the position you want her to have in your life. And a healthier life for all of you it sounds.
Good luck and keep us posted!