My G/F and I are serious about marriage. The one problem we have is complex and I'm posting it
here with the hope for some advice from someone older and more experienced who might have been
into the same shit.

From the start, my G/F's mother despised me. She was nasty on my first date with her daughter
and foul-mouthed, threatening me with violence if she discovered I mistreated her "baby" as
she calls her daughter.

I complained to Betty (my G/F) and she said, "Don't mind her, she's a fucking control freak."
She suggested that I just let her blow off her steam and say nothing. The weird thing is
that the mother had Betty when she was 16 and they look more like sisters, resembling
each other except for the fact that the mother has tits that look like torp**oes and Betty
has tiny nubs. Fortunately, I am not a tit man so they are wasted on me.

Our problem is weird. The mother (Nan) keeps wanting to pick a fight with me and it
pisses her off when I remain quiet. She eggs me on but I take Betty's advice and
let her shoot her mouth off.

About a year ago, when Betty and I started seeing each other, I dropped in, finding
that Betty was not home yet and had called saying she'd be at least an hour late so
I sat down on the living room couch and kept quite while Nan started in on Betty's
"ass-hole" employer. She said, "There are cold drinks in the fridge" so I walked
over, opened the fridge door and it hit Nan's butt, slightly. I apologized and
she screamed, "Did you do that on purpose?, grabbing me by the shirt collar." I
said, "Don't be silly."

We found ourselves to be physically close and suddenly we were at each other with
her tongue down my throat. I became extremely aroused and we started Frenching
and groping. She bit my neck and started moaning as she grabbed my now enlarged
cock. We tore our clothes off and fucked for at least half an hour, assuming
all kinds of positions. She went down on her knees a couple of times and
devoured my cock like a starved dog. She got most of it down her throat and
I never felt that weird feeling before. It was an amazing feeling.

This scenario began to repeat each time I see Nan alone and somehow we are
finding ourselves conveniently alone a good number of times. I am now
totally bent out of shape because I suspect I will lose Betty if she finds
out. However, I know I will continue to bang her mother or she will r-a-p-e
me repetedly, if Betty and I marry.

There must be some way out of this. I seem to be a total bastard and
feel like shit, but I am totally sexually hooked on Nan, who is 15 years older than I am
and not really a marital candidate of the first order. I know it is
insane but I can't stop. Neither can she. This is fucking insane.