A reasonable diet means being punctual for three meals a day, especially for breakfast, and the recipes need to be adjusted.
Proper exercise is to let you do some exercise that you can do every day. Being able to do it means that you can do it. If you go to the gym, you can ask the fitness instructor directly. If you do it at home, you can do some simple waist and abdomen or strength training.
It is important to keep a good attitude. It can be seen from your question that you are married and want a baby, but you have never been pregnant because of obesity. In this case, you should not only work hard on your own weight, but also change your mentality. If both husband and wife don't have any diseases, they will always get pregnant, not just because they are fat. Can only say that obesity is one of the factors.
My humble opinion is for reference only. Thank you.