It's fine to keep the baby if you would be happy if it ended up that you had to:
a) do it all alone
or
b) manage with him being an obstructive and negative influence and making things difficult on purpose (I am not saying he would do this, but you don't know him so it's a possibility)
Be aware that (in the UK), to put him on the birth certificate he needs to go with you to the registration or to sign and have witnessed a form which he gives you to take with you (or you need to give him the same form which he takes).
His being on the birth certificate gives him equal parental responsibilities (which he may or may not choose to see as "rights")
(If you register the birth without him, and he wants to get put on the birth certificate later, a court is very likely to grant him this.)
He would be obliged to pay maintenance whether or not he is on the birth certificate, but the CMS is not reliable and you may find yourself without any financial support for him.
If you are sure you want the baby no matter what, go for it. If you're not sure, don't rush into a decision to terminate.
You don't need to consider his feelings about whether or not to keep the baby because he knowingly took the risk that you could get pregnant when he had sex with you, and particularly when he had unprotected sex with you.