Husband not finishing vaginally

My husband has not been able to finish inside of me in the last couple years and I don’t know why. Most of our sex is oral, but when we have vaginal sex he never gets to the point like he is going to finish and I end up doing a hand/blow job. I don’t know if it is because he has gained a little weight and is out of shape so he gets tired or if my vagina just isn’t doing it for him 😂 Back when we were dating (6 years ago), we had sex a few times a week and it was never a problem. We have sex 1-2 a week now. I want to start trying for kids in the next couple of years but I’m afraid I’m going to have to jump from my mouth to my vagina in factions of a second to make sure I get all the goodies inside. I have asked him and he says nothing is wrong and it feels good, but I guess I just need a reason as to why his Mack truck is not taking a load off in this little garage.