In my opinion, a man has to marry them young before they start to explore their sexual desires with other people and keep a strong frame. If you live in Utah, and are a Mormon, you'd do well. For us, 30's and above, that ship has sailed. Seems the populous get tired and prefers short term relationships. Ladies start to test around the 3 - 5 month mark; and that can be a double edged sword. If you fail (give in), you're in her frame and she'll lose respect for you. You keep your frame and walk away, the relationship is over. She doesn't really care as she has a box of d!cks (her phone) in her pocket for new suitors to line up and replace you. She may come back in a few months, but aside from a few fvcks, the trust issues will prevent most for pair bonding.
It's a no win situation. Best bet is to enjoy your turn and stacking up resources.