To stop worrying, you many practice and do slow and deep abdominal breathing.(Google). This will keep you mind in control.While dong foreplay, keep your sefl in control and let her hurt more aroused.In case ther is a failure, take it lightly and do it again after half an hour. Second time you will be able to keep your control.If you both know kege exercise you may kegel each other by turn and you will have better sensations. hh
sounds like your stressed or at least stressing too much over it, try this......relax, lol, yes, relax, so like your stressing yourself out worrying if when its time to have sex you wont be able too, just let it happen, clear you mind from all stress, stress from work, bills , relationship issues.....worry if it will work or not, and enjoy sex, try new positions new foreplay