There are several red flags in your last paragraph.

• fighting all the time is not normal, and not a good foundation for marriage.
• he hasn’t changed in the three years you’ve been trying to get him to.
• he doesn’t show affection of any kind (sex is big but not the most important. Affection has far more numerous outlets than sex).
• you said you’re unhappy
• you said you feel like he likes it better with roommates

Those are many flags that this relationship isn’t fulfilling you anymore, and more sex won’t be a cure. You may love him, but that’s not all that goes into a functional relationship. Consider moving on because you deserve not to have to settle.