My 5 month old still gets up 2-3 times a night. feel worn down and overwhelmed. no sex with wife since birth. big impact on sex..did ivf. have 2 boys. any advice for me and relationship?

It will get better: Being a parent to young children is challenging. It is totally normal for a 5 mo. old to get up 2-3x/nite but as he gets older he will wake less often. I imagine your wife is at least as worn down and overwhelmed. You should both take a quality multivitamin and at least 5000 iu of D3/day in fall and winter. Take turns sleeping in. Hang in there; it will get better. But perhaps 2 kids is enough.

Sex when baby sleeps: First, work it out to have sex when the baby is asleep; its not spontaneous but it is what it is and better than no sex (and, you and your wife can learn to 'get right to the matter' quickly). Regarding the baby's sleep, its not uncommon. The issue is what is the cause: colic? intolerance of dirty diaper? You and your pediatrician should discuss and explore this issue.