Your boyfriend may be slightly more 'alternative' than you think.

IWFUA can mean a number of things.

Normally:

"I Wank [off (or indeed, 'off to' which would be marginally better)] Fucking Ugly Apes"

But sometimes:

"I Want Fudgey UnderArms" - have you ever seen Splosh magazine? You might want to get hold of a copy for him.

Also:

"I'm Waiting For Uncle Alfie" (What was the context? Does he want to play incest games?)

The final interpretation to be possibly extrapolated from such a nonsensical string of characters is as follows:

"I fuckin love text sex and I'm cumin as I text so can't type any more"

Good luck!

GHALKJDSFGY