New couple sex issues

Ki👸🏾

So I’ve been dating this guy for a little over 2 months . We all know everything is always great in the beginning of something new . I feel things changing a tad bit since we started dating. I enjoy sex a lot and have always been able to keep a partner up . but last night my guy couldn’t finish & I didn’t finish because he didn’t . The feeling was great for me. He says he was tired but something doesn’t seem right. We were going for about 30 min. I sucked him for about 15 min and I road him for 5 mins-ish . He was moaning and all , they didn’t seem fake . I was lookin him in the eyes. anyone have a clue to what could be wrong? What do you all think the issue is?