Hi funkbunny,
Speaking for myself I learng heaps from logging into Belly belly and fertility friend.

I'm biased but I wouldn't recommend Maybe Baby, I've found it unreliable.

Thermometre is a great place to start, and of course checking Cervical mucus (fertility friend explains the usual mucus pattern) . I also use ovulation predictor kits as an extra check (now i exclusively use those and don't temp anymore now I know my cycle well).

GP is a good idea too, and they may suggest your hubbie has his semen analysis done.

All the best !!!!