I really don't want to lay down lots of conditions, your access time with [our dd] is yours, but there are some ground rules...
Never drink and drive when you have [our dd]. I know you have done it with [his son], but if you do it with our daughter in the car I will stop your access immediately and I will be able to do this as you will then be deemed legally to pose a threat to her welfare.
With this in mind, if you have arrangements for any Sunday where you think you'll want to have a drink, I will be very flexible in arranging for you and [his son] to see [our dd] on another day.
Please always make sure [our dd] is supervised by a responsible adult, if you can't supervise her for any reason, while she's in your care.
Please bring [our dd] back at the time arranged.
I have no legal right to dictate what you do with [our dd] during your access time, unless it's harmful to her, so you don't have to lie to me about your plans, but I would appreciate having some idea of what she'll be doing. I realise you will be taking her to see your friends, and that you'll be taking her out with a partner at some point, and that's fine. As long as you ensure she's safe and happy in your care.
I'm sure if we can agree on these very basic 'rules', it will make things more pleasant for you, me and [his son] on Sunday handovers.