While my boyfriend always cums, I can give you a few pointers that he's said helps him cum quicker (we keep an open converation about what works, what doesn't, during sex).
Continuous motion: When you stop and go, although it may be exciting, it's gonna make him last longer. If you keep going at the same pace, rhythm, and motions, it gets him in the "groove" and it may be easier for him.
Use everything!: When I go down on him, I use my right hand to rub his base (as if I'm churning butter). I use my other hand to grab his ass, massage the back of his thighs, or reach up and rub his tummy.
The tongue: My boo LOVES when I stick out my tongue while sucking on him. I can't do it for too long, but when I do he's bound to cum all over!
The nipples: We found this out accidentally, actually, but whenever I suck on him and twist his nipples, he goes crazy. You can try it.
69?: Have you tried sucking on him while he plays with you? My boyfriend gets most of his pleasure from seeing me pleasured, so maybe that's the missing ingredient while you're getting busy down below
p.s. keep in mind that these tips pertain to one person...your husband may or may not go for it.
Good Luck! (And hey, trying new things is exciting in itself!)