Fat girlfriend; small penis

My penis is relativly small, right on 5.0" as a result anything other than missionary can be frustrating for me with a thin female.

But, with my 370 lbs girlfriend its impossible, I'm not sure it even works in missionary. It makes my frustrating situation more obvious.

I might have to break up with her. But she's my first girlfriend in 19 years so I dont really want to lose her.

Any ideas on how to bring up the subject of her losing weight?

>>1
WTF?  Her fuckmouth is RIGHT THERE, RedCream Clone!  5 inches of manmeat will block her windpipe as assuredly as anything.  As for her vag ... at 370 pounds, she surely knows she's lucky to have any BF at all, so let her masturbate while you bang throat.