This is reasonable for the first few dates. It is still a social norm for men to make the plans for the couple when dating. On principle, I think it should be more balanced. Women rarely ask men out date and consequently they rarely treat men on a date. However, social norms are what they are and men are compelled to plan and pay for dates as a result. Men who don't will be viewed as selfish and cheap and as you said, there's another man that's willing to pay. What’s surprising is it is actually men who drive this social norm (at least more than women). Consequently, many women feel entitled to men bearing the cost of dating for as long as they are dating. This may last months or even years.

From an equality perspective, I think couples should ultimately share the cost of dating. The details of this agreement is something that should be discussed by the couple. If one person has significantly more disposable income than the other, that should be considered. However, if a man or woman is unwilling to share the cost of dating at all, it is unlikely that they will be willing to share the cost of living once you are cohabitating.

If you are a woman in a long term relationship and you haven't chipped in for any of the dating expenses, rest assured your partner has noticed. It's very possible that he's not happy about it and he is trying to figure out how to bring the subject up. If you care, you should bring it up and work on an agreement. Ultimately, it's not about the money. It's about having an equal relationship where both people feel valued and cared for.