How to tell if I'm ovulating

I'm 3 months postpartum, exclusively breastfeeding and haven't had a period since last year.. Obviously my period still hasn't returned but I'm not on any birth control and my husband has been forgetting to pull out lately. How can I know when I'm ovulating to prevent pregnancy without birth control? I hate how hormonal I get when I'm on it and my husband hates condoms and swears he could "feel my iud" ugh.