Tent collapsing??? 🍆

Ive been with my boyfriend for a year and a bit now and at the beginning of our relationship sex was great. He was hard until well past he finished. Now Im lucky if I get to suck his dick before he is soft again. Ive been really supportive about everything and he swears it isnt me but I cant help think that maybe he is tired of me. I know its not the case but I think it goes through everyones mind at somepoint. I am wondering some reasons that could be causing this? Or if anyone has any experience and would like to share any advice is great. I fully support and love him, but i cant tell if its the constant video games or money stress or what. I just want to help.