I love older ladies so yeah. I just think about the "M" as Mature instead of Mom.
There are many different scenarios to this question.
1. Is she cheating on her husband behind his back? The intrigue and risk of getting caught could enhance the encounter. The fear of getting caught could also inhibit the experience.
2. Is the wife not getting enough at home and has a "hall pass" from her husband and out playing solo? Still somewhat intriguing but the risk element is gone.
3. Is the husband accompanying his wife on the soirée? Maybe as protection for her or enjoys being a voyeur. The idea of being watched could be intimidating for the lover or a bigger turn on.
4. Is this a cuckold activity? The wife and/or her lover demean the husband. The lover fells more powerful and maybe performs better.
5. Is the husband going to join in? This is a whole different dynamic. Only hetero sex, no MM interaction? Still intimating for some guys but most would do it.
6. Husband joins in with MM touching but no MM sex. Weird for many guys but as long as the wife is fully involved, then OK.
7. Husband is Bi and wants to be sexual with the lover. Most men draw the line here. Details should be worked out ahead of time so no surprises.
The twists and turns can go on and on. Maybe I am over-thinking this. Hell yeah, I'd fuck her.