When do you know when to have sex?

My husband and I had a hard time trying the first time we got pregnant. Which I also got diagnosed with PCOS. It was hard since I didn’t know when I would ovulate because my cycle were irregular. Now we are trying for baby #2 and last month I had a regular cycle. My husband doesn’t want to try as much and as we did last time. But at the same time I would like to get pregnant but I am having a hard time knowing when is the right time to have sex. Its our second month trying. The last week we have been doing it every other day but I don’t want to really do it every other day for weeks and since I am not sure I am regular. Last time i have to use metforman. I would prefer to do it on my own. What are your suggestions on when we should have sex? So I even follow the app? Last month I ovulated at this time last month I am pretty sure. I haven’t been able to tell if I have yet. (TMI- I get lots of Cm) how do you guys know when to have sex when you are trying and or have PCOS?