being relaxed during sex

How do you and your SIgnificant other stay relaxed when having sex? My fertile window is coming up and I've already told my husband so he's already freakin out. Cuz the past few night we've had sex but he didn't finish , just me. So I tell him just relax and try not to think about it, easier said than done. How do We not think of the importance of having intercourse with my hubby?? Lol how do y'all get thru it?