TTC second child with different father

[AKP79]

Hi - I'm TTC my second child with my husband who is not the father of my DS.

I fell pregnant straight away with my DS and heaping a lot of pressure on myself this time around, even though the circumstances are completely different. We've been trying for a few months (which I know if nothing in the grand scheme of things. This time round I'm in my late 30's and obviously we're talking about a completely different set of swimmers.

Questions are: is it worth trying out an ovulation kit or are they a waste of money? I've read people talking about body temperatures and that being a good ovulation indicator... how does this work and what am I looking for?

Anyone else in a similar boat?