TTC #1 and now I'm thinking about backing out.

My husband and I are trying to conceive #1 he's 44 I'm 39 - we tried <a href="https://glowing.com/glow-fertility-program">IVF</a> 3x n failed, my husband had surgery for high DNA sperm fragmentation, then we had 1 natural MC. We've been trying since Oct 2014 and now I'm thinking about giving up. We got married in 2012, so we started late.
Who am I kidding I'm almost 40. He'll be 67 when the kid graduates from college. I thought we both wanted kids but Suddenly today it hit me! "Why am I trying to kill myself over this?!" I must be nuts! Am I trying to hold onto my 30's? This is maddening. I'm too old for this. This is so stressful. I've gained over 20lbs. When's a reasonable time to give up? 
I can't live like this. I'm tired of peeing on sticks and getting my hopes up only to be crushed month after month with BFN. I'm so jealous of pregnant women, that when I see one I get angry. Everyday my odds are decreasing. Time is working against me and yet this seems to be the only thing I care about right now. Is this b/c "You always want what you can't have?" When can I throw in the towel?