TTC fiancé is 40 im 25 . need positve stories

Hey everybody ! I've never posted on here but I'm desperate and need feedback . my fiancé and I have been trying TTC for 4 months now . he's 40 years old , pretty darn healthy . I'm just worried we'll never get pregnant . he has 2 kids (16,17) . is anybody in my position ? or any couples TTC or HAS conceived with an "older" partner in their 30s-40s ? I'm trying not to track this cycle because I'm stressing myself out . he's also starting to doubt his self thinking his baby juice is no good 😢😢