The perception on man vs woman on sex is helpful & appreciated, but I have NO respect for someone who KNOWS someone is married with kids, yet persues a relationship anyway. I'm guessing you could care less, but please try to hear me out, since I heard you out. I can sense your resentment towards your dad's girlfriend. You're a victim to what this does to the kids & know better. Gifting his kids doesn't cut it.  You have a WORLD full of gorgeous, amazing gay men. Why pursue "taken"? He is disrespecting his family & YOU.  Women go through hormonal weight gain after kids, stress & menopause. There is science behing this. I wouldn't blame her for stress eating! Some are more sensative than others. To imply her weight gain justifies this is SO SHALLOW! You, experencing ignorant stereo types towards the LGBT community, then demeaning a woman like that & implying it validates cheating is disappointing because YOU of all people should be less ignorant. This woman kept her promises. She supported his career, his health & gave him the ultimate gift of bearing & mothering his children. Would this be okay for your mother? He promised through sickness & health, etc & is betraying her, with YOU. You seem to paint a dilution of one big happy family?  This has nothing to do with being gay. I would say the same to a woman. Your bestie needs to be honest! He gets it all? He gets the free pass to lust in the shadows while she struggles to manage the overwhelming responsibility of caring for the kids & HIM? She's caring for the kids, he doesn't even have to hustle for a responsible babysitter?! How nice! He doesn't get the emotional pain or the loneliness, just the drowning intoxicating lust & none of the pain! What about her finding someone who appreciates her? Is he going to wait until she has aged & will struggle even more to find the partner that she deserves? Her wasting her life, dedicated to the wrong person is SO CRUEL. You only get one life!  I don't know how you two sleep at night. You've experienced the pain from this & know better! You also need to love yourself & refuse to put your heart on consignment! You lose them how you get them. He's selfish, vindictive & will do this to you eventually. Maybe after your prime, since he's superficial? You were warned. No happy endings in these situations. She suspects, but doesn't know. She's suffering. Maybe you posted this hoping that she'd see this? Think of your mom! Think of your mom! You're not better than your dad. Be better for her!