When is dating two people ok and not ok?

The problem came because he only takes me out in the afternoon. He answers all my calls on weekdays, not nights or weekends. He talks of the future with me. We are falling in love (mutual) but something is wrong and he clearly states he is available. I discoverd a much younger gold digger holding him under the barrel. He has no commitment to her but she is stalking him and he seems to feel some obligation. He is ridding himsrlf of her and I am not seeing him until he does because she is nuts! Yet what about the trust? Is that lost now?