Me and my fiancee have been trying to conceive for four years.

I'ma start off by saying that I am totally confused about me not being able to conceive with my fiance. I dont want to put my business out there but Im a little confused and seeking for answers. Me and my fiance has been together four years. Our first couple of years we really wasnt ready for a child so trying was out the question. We ended up splitting for a few months and I slept with another man and got pregnant:smileysad:. I carried for two months and then had a miscarriage. My fiance and I got back together and resolved our issues and figured that it is time for us to start our family. I am not sure if I have irregular periods or not. A few months they come and go just fine as if they are normal and then I would say a few months down the line they start staying an extra day or two; or they would stop and then wait 4-5 days and then come back as if im having another period for that month. Its confusing and stressful. We are really wanting a baby and hoping for the better. I know I can get pregnant due to my previous miscarriage. I use to question him being able to produce but he states that before we met he had another female pregnant but her parents talked her into an abortion.