My man finishing before me.

This sounds so stupid and am even a little embarrass about posting something like this up. But I need some type of advice. So me and my Boyfriend have been together for about 6 years. We do not live together either. Am 28 years old and he's 33. We have what I call a very satisfying sex life. We are very comfortable with each other buddies. And always for the most part communicate very well when it comes to sex. lately for the past few months we only been having sex ounce a week. Due to our different work schedules and stuff. But also lately when we been having sex my boyfriend has been finishing before I get to have my big O. And like I said before we have a very satisfying sex life I always get my Big O with him. But lately everytime we have sex he's done. And I didn't even get to finish. But to make it worst ounce he's done it's like he's done. He's tired and he can't get hard again for like another 30mins and by then. We don't want to do it again. The other day he came like two times in a row and I still didn't get to have my share of Cumming yet. I feel so bad because I kinda got upset because I was almost there and then it was like nope no Cumming for you today... again. So he got into a argument. And i basically ask him wtf is going on with him. Btw my boyfriend is very healthy and very active. he thinks that something may be worng with him...But what if it's me that has the problem?? I love him so much and I wouldn't want to be with no other man but him. But am I out growing him??