why is my boyfriend doing this?...

Alex • 12.20.15 E🔒❤️ Mommy to one in heaven ❤️ 16 years old
I just turned 16 and I'm on birth control (implant rod). My boyfriend (17) cums in me a few times a week. Lately whenever we cuddle he will put his hand up my shirt and rub my belly. He'll also just rest his hand up my shirt on my stomach. Does anyone have any idea why he would be doing this? I have no clue why and I want to hear others opinions on why you think he might be doing this!!