I''m assuming when you say you "had sex," you're referring to penis-vagina sex, so will answer your question based on that.
Having a foreskin that doesn't retract is referred to as "Phimosis." It can be a very minor condition which needn’t affect your sexuality. In most cases, having a foreskin that doesn't retract should not cause any problems during penis-vagina sex.
In most cases, this should not cause any problems for you unless it's causing pain. If it does cause pain, you need to see a urologist. Until the age of 10 years or so, only about half of all uncircumcised boys can retract their foreskins. This figure goes up as men approach adulthood; however, some men reach adulthood with a non-retractile foreskin with no problems at all.
Other men, however, may want to make their foreskin retractable. The foreskin may be made retractable by: gradual, gentle manual stretching, and/or application of topical steroid ointment (provided by a physician). If you decide to try manual stretching, remember that stimulation can irritate unless you use lots of lubrication. Dr. J
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