Age gap

Hey everyone I really need some advice and tips on how to make my age gap with my boyfriend a bit easier. 
I'm 16 about to turn 17 and my boyfriend is 23. Yes I know it's a big age difference but when him and I are together we hardly notice it. 
Recently we have been arguing because he says the age gap is getting too much to handle but we haven't had any problems with it in the whole 8 months! 
I think he might just be stressed but I don't want him to end it when we have a perfect relationship and the age problem will go by the time I'm 18. 
Please give me tips or advice