should I get checked?

Beka
Please remove if not allowed.
I'm 23 and me and my 35yr old s/o have been trying for 18months to conceive. I lost a baby September 2015 at 8 weeks but haven't managed to conceive since. We have sex 3/4 times a week on average and was wondering if any of you wonderful and strong ladies had any advice? 
I might be being stupid but my boyfriend has had his sperm tested before and was fine xx