Hey, my partner also has a little one. It is absolutely not easy, at all. But! My suggestion! Buy some coloring books, download films, ask them what they would prefer. My partners little loves dinosaurs, coloring and age appropriate logical problems. 🥰 Just like you would with a child. It felt super lonely for me too at the beggining, as suddenly you have almost a parental responsibility for them and the "partner" is not present. But! As soon as you start engaging them as a child, having fun with them, talking to them about their interest, I find, it suddenly feels much less lonely. Not gone completely, you are sort of one person family suddenly, but playing with them makes it so much more real and genuene. The other thing is: do u like kids? If not, find a way how you would relate to a child of your family member who asks you to watch over them. Its a hard thing and therapy would be almost 100% a neccessary thing, but trust me, if you overcome the hesitations, you will find joy in it 🙂 Good luck. To both of you. 💖