Here's my thoughts about your argument.

1) You seem to be equating "moral" with "genetic predisposition to survival and propagation." You're arguing that men are programmed, through evolution, to cheat, and that cheating is therefore moral.

2) Cheating is not merely having sex with two different people. Cheating is promising, explicitly or implicitly, complete fidelity to a single person (the spouse or other partner), and then breaking that promise. A person who has not promised himself to a single individual cannot cheat. Thus, if you cheat on someone, you are in fact breaking a promise and being dishonest. Promise-keeping and honesty are principles fundamental to every aspect of our civilization.

3) Similarly, it is possible to fulfill your desire to have sex with multiple women without cheating. You merely have to tell the person to whom you have promised fidelity that you wish to end the arrangement. She can then either agree with your decision and stay with you while or terminate the relationship. In this case, no cheating or dishonesty occurs.

4) One of the primary functional purposes of monogamy is to ensure that children receive the care and education that they need to grow to become respectable citizens. The structure of the family has changed dramatically in the last few days from the men-work-while-women-raise-the-children model that has existed for millennia, but even so, it is still extremely difficult for a single parent to raise children. Children raised by a single parent are dramatically more likely to be involved in criminal activity and less likely to achieve financial success in life.

A few thoughts on some specific quotes:

sexual infidelity doesn't directly hurt anyone. Two people get to enjoy sex. The lover who has been cheated on only experiences anger and distress because they have been conditioned by society to not accept this.

The why of the partner's distress does not change the fact of the partner's distress. If you cheat, then you will hurt your girlfriend, and there's no way to rationalize it away by claiming that she is merely so conditioned. Additionally, if, as so often happens, children result from both relationships, then the damage goes deeper into economical and long-term familial territories as I mentioned above in point (4).

The majority or women have overwhelming genetically programmed desires to prevent their partner from acquiring free babies elsewhere

This would seem to be a direct contradiction to the statement that I previously quoted.