Petite girl, firs time dating hung guy, experiencing some discomfort

hi, i'm 23F and the guy im currently dating is 32. I'll get right to it, this is the first time ive ever dated a guy with a really big dick, and while its honestly very pretty and nice, im struggling with it a little bit, lol. I've always been very petite, and while im not inexperienced with sex, this is the first time im running into a bit of an issue. i asked him if he had ever measured and he said yes that his dick is 8.5x6.5" (he just got out of a LTR and i guess he and his ex measured for fun). the sex is actually really great, we've probably only done it 5-6 times as of now, but PIV insertion has been difficult, and it hurts the next day. he is really kind and sweet and willing to go slow with me every time, but ive been asking him to only put it about halfway in. he says he doesnt mind, but im worried he might eventually? a couple of times he put it in slowly all the way to the base, and while that felt amazing, i couldnt let him do it for too long. i guess what im wondering is, do you think ill get used to it? do you think he'll get tired of having to be so gentle with me and not put it all the way in? i dunno, i rlly like him and i just dont want him to get tired of me because he cant just easily fuck me, i guess. so far, we've been pretty open in our sexual discussions, but I dont rlly wanna ask him if he sees this as a problem, long term.

side note: when we have sex, its like a normal amount of time before he orgasms, but when I give him oral (which is also a bit of a struggle since I have a small mouth, lol). it seems to take him a really long time to cum. I dont mind it, because i do like doing that for him, i just dont know if its because im not doing it well, or do guys with bigger dicks just take longer to cum from blowjobs? Any advice/insight is welcome. Thanks!