going soft during sex

my man and i have been together for almost 9 months, & i gave him my virginity about 2 months ago. he was not a virgin tho & before me, it had been almost 2 years since the last time he had sex. we’ve had sex about 5-7 times between then and now, and every single time, he goes soft in the middle of it. it’s easy getting him off with oral but intercourse just isn’t doing it for him & he said it’s because his body “has to get used to sex again” but like we’ve had this issue for months. & for about 1-2 weeks, he’s tried to refrain from anything outside of intercourse in an effort to “train his body” but we tried again today and he still went soft even tho before today it had been about a month since the last time we had sex. i don’t know what to do but this issue is really taking a toll on our sex life and i really want to know how to help him fix this. any advice??

UPDATE: i think i figured out the problem(?) but i had heard that some people have trouble comfortably switching from one thing (like oral or hj) to another (sex) & all the other times we tried, i had sucked his dick before he put the condom on & he went soft but we tried again today and all i gave him for foreplay was a little bit of jerking off & not only did he stay hard, but he came too!! im probably more excited about this than i should be 😂 but maybe oral just isn’t a good foreplay for him? idk. i just hope that this was the actual problem & solution & not something else lmao