Delay ejaculation issue of my husband.

Hi 2 years passed of our Marriage but I have face the problem of delay ejaculation of my husband from last 4-5 months Because of this problem I am not able to extend my family planing Please suggest what should we do now because it's also give tension to my husband too. He is very good in Sex but it's take 40-50 mins for ejaculation. I have tired after 30 mins of sex and because of this we are facing problem that I can not pregnant. Plz suggest that can we take IVF treatment for pregnancy or should wait for natural pregnancy? Plz suggest I am in very tension because of this issue. And also suggest some good doctor for this problem treatment. And aside I was pregnant in April 2017 but that time my baby heartbeat is missing so because of this my baby was dead in my ovary. After that case we were try so many times but I have not conceive any single time. We are also follow the egg fertilise periods of after 14 days of periods date but still no result in our hand. Kindly do d needful