My fiancé's medication stops him from ejaculation

My fiancé has been on bipolar medication for the past 4 years now. 
(Yes dealing with a bipolar spouse is hard but hey that's love)
We've been ttc for 2 years and I really think his medication could be the culprit. Today he woke me up to morning sex and I was like yasssss! But I realized afterwards "he didn't get his". He also agrees that it's due to the medication. 
Clearly, having to play with the dosage could be tricky as he's been trying to find the right combination, and whatever dosage he's at now works wonders. He also has a lot on the work front so changing the dosage could be tricky or a trigger for depression or our worst nightmare becoming manic. 
Times like this gets me down because I feel like we will never conceive... I'm at the age where all of my friends are pregnant or just had a baby and I can't help but to get jealous. I know we would make great parents. 
If anyone out there who has a medicated bipolar spouse or if you are dealing with the same disorder could you please send some tips or any advice you've tried that worked out will be greatly appreciated.