HELP! Too much stamina

So I’ve been with my partner for 10 months and we have had sex multiple times and it’s great the only issue we both have is that we can both go for hours on end. Basically we both can go for hours. But it gets difficult to come because at one point or another one if us gets tired and out bodies start to hurt because of all the fast movement. We have both orgasmed with each other before but it’s gotten difficult for us because we get so tired. We’ve tried different positions and new things but it’s still frequent that neither of us come. Let me know what you did if you have the same problem. I