I am sorry to say this, but IMO "withdrawal method" is NOT a method of contraception but one possible way of trying to conceive!! It is SO unreliable that I would really encourage you to do a test ASAP so you know where you stand.
I am with all the husbands/partners/boyfriends out there who "will not consider another method"! It is not them who will be stuck with a decision what to do if an unwanted pregnancy occurs and they will not necessarily have to live whichever way that decision went!!
IMO it should only ever be considered if a couple wish to space their children but would not be too upset if they conceived anyway. For all of you that it has worked for for several years, thank your lucky stars! I am really not sarky/flippant about this, but I deal with too much misery in regards to this kind of misinformation in my professional life to not feel strongly about it.
"As safe as condoms" - right and wrong. 85% quoted for condoms is an average. An inexperienced couple fumbling in the back of a car have a MUCH higher chance of getting it wrong then a longterm couple who have had lots of practice using condoms. And then there is the prevention of STDs...
Sorry again, Luce, rant over, but please do test so you can consider your options. If you are not pregnant (and do no want to be) please, please, please change method of contraception.