All things aside, can you satisfy ALL his sexual needs? Do you watch porn with him or do you expect him to finish himself off without any aids?
If you loved him that much, you wouldn't have slept around during the break. Now you must be thinking, "but it's my right, we were on a break." It's also his right to keep those pictures on his computer and fap to them but you have been depriving him of that right.
Conclusion is that both you and your boyfriend/ex don't know how to love.
Ezekiel 25:17. The path of the righteous man is beset on all sides by the inequities of the selfish and the tyranny of evil men. Blessed is he who, in the name of charity and good will, shepherds the weak through the valley of the darkness. For he is truly his brother's keeper and the finder of lost children. And I will strike down upon thee with great vengeance and furious anger those who attempt to poison and destroy my brothers. And you will know I am the Lord when I lay my vengeance upon you.