You could try explaining why you need it and the importance of you getting the quiet time in the morning. Like if you don't get it in the mirning it could or would throw off the rest if your day or mess uo your set schedule if you have one, hopefully they would understand and accept it.
If your partner doesn’t initially understand that you need quiet time to yourself in the morning, then you and your partner need to talk about it at a time other than the morning. Help them understand by having a frank talk about it. Show them how giving you this time can help you both, and listen if they need your support or have questions or objections.
It is not mandatory that your partner understands. It is, however, mandatory that your partner gives you that time. The other way around, it is mandatory that you take your time. Then your partner will understand.
Have a clear conversación be patient with the feeling og the persona you love and show them that you care but still need time by yourself