I'm sorry, but I don't see much of a relationship here, he's never with you! Get rid. It might be just the money he likes about this other woman, or she may be exceptional for a woman of her age, but then he still doesn't consider your feelings. Contacting her wouldn't do you any good, you could be saying one thing to her, and he could phone her the next day and say the opposite - then go off again. You can't trust him, and once the trust has gone then it's pointless to carry on, you'll only be wondering if he was going to stay or stray again.