anal fissures

Just wondering if anyone has had any experience with anal fissures, I have had this problem for a couple of years now of on and off fissures that usually heal up pretty quickly but lately they have been so much worse with haemorrhoids on top of it. I've tried fibre vitamins, Vaseline to lubricate the area and nothing seems to stop them from opening back up again. My boyfriend wants to have anal sex which I've done heaps of times before but with this issue it's pretty much impossible so looking for anyways I can fix it