All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Marriage in Islam has some conditions and pillars and the marriage contract is not valid unless it fulfills some conditions that we mentioned in Fatwa 83629, the most important of which are the consent of the guardian and the presence of two witnesses.
If a Muslim woman has no Muslim guardian, then the one who marries her off is the Muslim judge or whoever acts on his behalf in non-Muslim countries; for more benefit, please refer to Fatwa 88488.
Therefore, if the situation is as you mentioned that your husband only did that procedure as marriage, then it is not a marriage at all; rather, this is a kind of cheating that leads to committing Zina (fornication or adultery). Hence, you are not considered his wife by this and it is not permissible for you to allow him to have sexual intercourse with you, and you are obliged to repent to Allaah and stop doing this sin immediately.
If he insists that you are his wife, then you should take your case to one of the Islamic centers so that they will separate between you and him. What he said that everyone considers you as husband and wife does not make any sense.
As regards abortion, it is forbidden even if the fetus is at the Nutfah stage (before 40 days of pregnancy) according to the preponderant view of the scholars so, whoever did so, or helped in doing so, is obligated to repent to Allaah. If this fetus was aborted after it has taken form [which is after 40 days], then the one who carried out the abortion is obliged to pay a Diyah and this Diyah should be given to its heirs but the killer does not inherit anything from it if he/she was one of the heirs. For more benefit, please refer to Fatwa 102388.
Finally, the following matters should be mentioned:
1- One should avoid being lenient about having illicit relationships as it has bad consequences.
2- The children that are born out of an illegal relationship, are not traced back to the fornicator/adulterer.
3- Marriage in Islam does not require any specific rituals; it is not necessary that this is conducted by the Imaam of the mosque. It is enough if there is proposal and acceptance between the husband and the guardian of the wife, and the presence of witnesses.
Allaah Knows best.