@Heartofstrings presumably you agree that you need to lose weight and want help with that as you have posted in the weight loss section, so I’m not going to try and give you any relationship advice! If you aren’t happy that he brought it up/question his motives etc then that’s a different issue.
Starting point is what are your stats - height/weight? What sort of activity level would you say you are at? You need to work out what your TDEE is and then subtract some calories. Use this website: tdeecalculator.net/
Some people will tell you to reduce by 500kcals per day which is supposed to give you a loss of around 1lb a week, but it’s not an exact science (the info out of the website or the calorie deficit you need).
For example this website tells me my maintenance calories are 1,800 per day but I know I can lose on 1,600-1,700 per day so I am probably under estimating my activity level slightly.
I know it’s not popular amongst diet and fitness purists, but I have always had success with slimming world too. I shouldn’t like it, because I do have a health industry background and I do appreciate its flaws in not actually educating people about the mechanics/science of weight/fat loss, but as long as you actually cook, and not rely on overly processed shite like muller lights, then it does encourage a balanced diet full of lean proteins, fruit and veggies.
If you are very overweight, I’d say focus on the diet aspect and not worry too much about exercise except upping your general activity levels (I.e. buy a cheap Fitbit type watch and count your steps, trying to do 10k per day).