Lust is when you have a strong sexual desire with a person. If you're lustful, you always think about sex, the desire of sex, craving sex from someone all the time. It is natural to think about sex and having sex with a person you love. Having sex is part of love, it is not love but part of it. Love is when you have those moments of strong intimacy towards something you both have in common(not just sex) If you love the person, it is okay to have sex, but just thinking about it and feeling that that is the only reason why you want to be with him, is not love. When you take the time to do the simple things like getting groceries, walking in the park, helping each other when sick, being worried if the person you care about is OK, and letting the person have some space to their own, is important.
Want to know how to get the spark back? what is the reason why he broke up with you? maybe because you are too needy or clingy? The way to stop arguing before it leads to huge fights is to talk about how you feel about the certain topic without getting mad at each other. Let him have his space, do not make instant accusations towards him. When it all comes down to it, you need trust, patience, understanding, acceptance of who the person is(even if it is negative) being there for the person at their hardest of times and sacrifice. Quit being needy and causing unecessary drama, try to avoid a conflict before it starts, don't yell or raise the voice and don't give attiitude, have repsect.
The way to keep from having sex is simply going out. Don't stay in a house all the time, make sure there is company. Just a simple, push of the hands while making out or just a simple "no" is all you need. Make sure to find out what made him like you in the first place.