Trying to conceive

Hi,

Trying to fall pregnant but didn’t have to try with my first one so not really sure when the best time to have sex is, my partner is fifo ( works away for two weeks and is home for 2 weeks) of the month and if I have worked it out right I’m fertile and ovulating when he is away right up until August when his roster may swap weeks, is there any chance at all of us falling pregnant? As from what I’ve heard you need to be fertile or ovulating to fall pregnant.

I’ve also heard that sperm stays alive for up to 5 days if this true ?

Thanks in advance for any help