Flucations

I am wondering that why the flucations seen while testing, after five years of marriage life.
Below test are within 18 months
1st test Sperm 4 million - Motile 10%
2nd test Sperm 12 million - Motile 10% (without medicine intake)
3rd test Sperm 18 million - Motile 20% ( with Medicine)
4th test 32 million - Motile 50% (with Medicine)
5th test 40 Million - Motile 0, Sluggish 50% & Dead 50%, last test after 30 days.
6th test 18 million - Motile 30%.
Please clarify my doubts and suggest the correct treatment