Don't do anything you'd come to regret. He may not be as madly in love with you as he claims. Having a wife and three kids isn't something you can easily walk away from, but chances are he's looking to have the best of two worlds; a loving wife at home, dinner on the table as soon as he walks through the door after work, three kids that are still young enough to make him feel youthful, too, and then a young girl who can't see the wood for the trees willing to sneak off, and jump into bed with him the second he feels he's safely away from his family. Most cheats will use the "my marriage isn't what it was/we rarely have sex any more/one of us is always busy/we never get time alone now that we have kids" excuses, and they'll pounce on the first sucker who falls for it, when in reality, their family life is just fine, and they're only after some cheap thrill with a more attractive and/or younger lover. Yes, there is a chance he's being honest, but take a step back until you're 100% certain he wants more than sex with a girl much younger than his wife. If you believe he's genuine, don't forget to consider that, if you get together, his wife and kids will always be a part of his life, and despite them being of a similar age to you, his kids may not immediately be forgiving that their parents have split, and their father has moved on to you almost before they could blink. TL;DR There's more to this than how you both feel, so don't allow yourself to be naive to the truth.