Amitriptyline and Vaginal Irritation or Semen Allergy?

This is my problem: i have recently attended a consultant in urology as i was having recurrent UTI's and symptoms of cystitis for well over a year. i had a cystoscopy and ultrasounds and uro-dynamic tests done and it was shown that my bladder size, capacity and function was diminished by 40% than an average bladder and as i had increased urgency/frequency i was putting my urinary tract and bladder under stress and so it would become inflamed/infected. The consultant suggested i start taking Amitriptyline (TRICYCLIC ANTIDEPRESSANT)as i was told it would suppress the urgency/frequency symptoms and hopefully eradicate the infections and symptoms of cystitis. My last appointment with my consultant was in early dec 2011 but the problem i have been having was not really that apparent then. What i have noticed since, and what i feel may be a result of the medication i am on, is an increasing pain in the vaginal area immediately after having sex, but only during sex when my partner ejaculates without the use of a condom. we have been using condoms now as the pain gets so bad that i am still in pain in that area a few days after. the feeling is like a horrible stinging pain all on the outside of the vagina, i feel like internally i am tight and swollen and having sex again a few days later can be extremely painful, even when we use a condom. i have not noticed any unusual discharge, just the immediate and increasing pain after i am in contact with his semen. i have read about people being allergic to semen and that it can occur sporadically. i have been with my partner nearly 3 years and there has been no issue in this regard until now. i started taking the medication in September. i take 50mg per night every night. It has done wonders in terms of my urological complaints but i am wondering now is it also having an effect on any reaction i have to my partners semen. has anyone heard of there being this interaction with the two or does it increase the likely hood of having a reaction? how do i over come it if it is due to the medication i am taking? and if not, what can i do to stop the pain without using condoms? many thanks for listening. LG