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You seem to be having a problem of secondary infertility
.The part of sperms does come out of vagina and is normal.Presently you can try few tips like:-
-when you have sex do not get up for at least 2 hours after sex so that most of the sperms are retained inside so keep lying.
-Do sex on alternate day from 10 th to 21st day of start of every period if you have a regular periods after 28 days.
You can try these things first and if you do not get result in 2 months you can consult a Gynaec and get these things examined and investigated
-if your husband is a smoker or has drinks few times a month then get his semen analysis
done to find if the motility and the quantity is good.
-if you had first baby by LSCS (operation) then you will have to get tubes checked for patency by doing a HSG
-and if required she may even ask you to do a follicular study
to see if you have proper ovulation.