Define love in this context… It may be that you feel no romantic/sexual love for one another… And this could be temporary, especially if your child is newly-minted. Alternately, it could be that you've simply grown apart, but still care for each other AND your child enough to continue forward assuming the alternatives to be worse.
But there are many, many alternatives. Amicable (or not) separation. Divorce. Various forms of non-monogamy (who said you had to get all the love in your life from one person?). Whatever you choose, it should be both a conscious choice, and one made together as much as possible.
Which means, before you do anything else, you should talk things over, and see what you both want as individuals, in your relationship(s), and for your child. Then throw out all your ingrained assumptions and traditional rules, and just figure out the best working solution for everyone immediately involved, and stick to it.
Also, you might try volunteering with the elderly for a bit. It's amazing how easy it is to assume that people stayed married in the past out of love – and how different the reality was, and oddly how much more mature and open-minded compared to the atmosphere today…