I was circumcised as an adult. Although my glans toughened up so that it’s not irritated by clothing etc., once I had adjusted it made no difference for sex. The condom problem is, I think, more about the fact that you spend years masturbating without a condom and you get used to a level of stimulation that is ideal for you. If someone else masturbates you it never feels as good as what you can do for yourself.
Try stroking your arm on bare skin, then through a T shirt. Once you adapt the sensitivity of your arm to being stroked through the T shirt, it doesn’t feel much different. Same with the condom.
It can help if you re-set your mental stimulation level. Take a few days off masturbating etc. until you feel really desperate, then have sex with the condom on. The actual sensitivity of your penis is the same as if you had not taken a few days off other sexual activities, but you should still find it much easier to reach orgasm with the condom on.
I used to think it was going to be harder to feel much with a condom on and it was this belief that reduced the sensitivity far more than the condom itself did. Get used to cumming with the condom on by not having other stimulation between sex with your girl, and you may find that it is not because you are circumcised (plenty of circumcised guys suffer from premature ejaculation and apparent over-sensitivity). It’s just about making it as normal for you to reach orgasm through having sex with a condom as it is to masturbate.