Partner and sister

Hey everyone, Just wanting your honest opinion and how you’d feel about this!, so long story short and backround, my partner and I have a 3 month old I have no license We live with his sister (she’s 23) has a license and I pay for her groceries and dinners as she doesn’t have a job) So anyway most of the time my partner and i go and get a morning coffee everyday, and I don’t get out often as I don’t have a license, so this little 10 minute outing is really good for me and Bub but most of the time my partner ask his sister do you want to come for a drive and if she says no then he asks me but he never asks me. He also says let’s go for a drive to get dinner to his sister while I stay at home with Bub, last time though they sat and ate their food in the car park and by the time they got home my food was cold and I was upset because I’d just gotten Bub to sleep and I was so tired I just wanted a hot meal but this is quite re occurring. Also I’m not a smoker they both are and always go off on walks or go away and have a ciggy but for long times and his sister always takes him to have a chat, it never used to be like this his sister had a boyfriend and I was pregnant and he was he very attentive with me but now she has broken up with her boyfriend and I have given birth it seems like he would rather be in his sisters company.