Boyfriend can't stay hard

My bf is in his early 30s and when we first started dating he could fuck for hours and go again and again. Now it's only been 6 months together and he has trouble staying hard and our sex sessions are really quick. He usually wants blow jobs and always gets softest when I'm riding him. I'm wondering why is this happening? Is he already bored of me? Is my pussy too loose now? Is it cuz he's old? Lol. Wtf is going on. ?? I feel like he's not as attracted to me anymore 😢