Yes, they could certainly have sex.
Homosexual men and homosexual women manage it!
The main question is basically they would not evolve sexual organs, but the enjoyment access of these parts is just a LOT of nerve endings hooked up to the reward (pleasure) centers in the brain.
Presumably, your people do still have reward centers in their brain, and still have feel good emotions for pleasure, love, etc. It is entirely possible they also evolve something akin to sexual organs with extreme pleasure to promote (as a survival strategy) bonding, love, commitment and partnership. Which is much of the reason we evolved both these emotions and the pleasure of sex. Note that not all animals share sexual pleasure; for example many fish lay eggs and males fertilize them after the fact. We evolved this pleasure mechanism to increase the chances of us having sex that led to reproduction; but equally evolution could evolve an equivalent sexual pleasure center in your species to increase the chances of them bonding to raise children and increase their own survival rate by committed partnership.
Such a sexual organ would not be linked to intercourse, per se, it would be stimulated by other means, but could be just as pleasurable, and orgasms could also be involved.
For example (and being intentionally clinical) lesbians can bring each other to orgasm, orally or digitally, without any vaginal penetration at all. The necessary organs are exposed. Your race may have developed similar organs, and by culture this organ is kept private and only exercised in intimate committed relationships (and like us, maybe just for fun outside of such relationships). But, like lesbians, neither partner need be dominant over the other. Besides that, they can kiss, hold hands, lust after beautiful bodies, fall in love, etc.
Added: Evolutionary Clarifications
In response to comments; "why would they want to have sex?"
I promise this tour of real life will help answer this question; and I hope it improves my answer for the more technically oriented.
Pleasurable sex, pairing love, familial and parental love all evolved, they did not spring forth with life. Many dinosaurs (Paleontologists have concluded) did not mother their eggs. Like sea turtles, they laid them and left, when they hatched the hatchlings are on their own with an instinct to reach the relative safety of the sea, on their own.
The instincts to nest evolved later in dinosaurs, it improved the survival rate of the hatchlings. The same for the other mothering instincts, hunting for and feeding the young, and protecting them from predators. All of these are a greater investment for longer-lived animals, and are not driven by logic in early animals but emotions. Collectively, we could call these "motherly love" and attachment.
Now in a two-gender species, evolution takes a long time for the males to feel this same kind of attachment; but in a single-gender species, all individuals are born with the same instincts: The genetic "invention" (or occurrence) of this behavior would be passed on instantly, and by whatever survival advantages this conferred (we know it confers some) the genetic basis will spread through the population and drive out the alternative within a few dozen generations.
We can expect a similar effect if this parental love for offspring is transferable to non-family: We see at least this IRL for children now, men and women do not have to be the biological parents of a child to love a child, or children. Men have risked their lives to save children in danger they have never seen before; and said afterward they do not remember even making a decision to do that: It was instinct.
Since pairing or partnering is also an evolutionary advantage, we can imagine this parental love being modified into pairing love; mutual care for a partner. Two is actually the sweet spot; there is a significant advantages conferred by two people working together, that does not increase greatly by making it three or more. It increases, but not as dramatically as the jump from one caregiver to two. e.g. The dramatic difference is one can protect the children while the other hunts and gathers food, or one can keep watch while the other sleeps, or if one is sick the other can handle the load. No big "game changers" like this occur by adding one more to the mix.
As for pleasure centers, ours are located near and in the excretory organs; presumably this species also has organs to eliminate solid and liquid waste. I am not a biologist but I think it is clear the excretory organs evolved first and when pleasure centers evolved, they co-located there; perhaps the necessary nerve pathways are close by so this is the most likely place to evolve a dense bundle of nerves for pleasurable stimulation. There is some little pleasure in relieving one's self, and evolution is littered with this kind of re-purposing, doubling, and opportunism. Does it make sense to evolve a pleasure center that has no other purpose? Many biologists think the clitoris is exactly that, it serves no other biological purpose and is not necessary for reproduction. In fact as an aside, the external clitoris is not even very well placed for stimulation by vaginal intercourse. So yes, evolution might do this.
I will also note that evolutionarily speaking, the more intelligent a species becomes, the longer the "childhood" phase of development. Primitive brains run on instinct alone, big brained animals (like us, like elephants and dolphins) are not born fully brained, their brains develop over years and require learning and teaching and physical care while that is happening. And this can plausibly require even more commitment from a pair of parents; particularly if the species evolved in a more dangerous environment (predators, poisonous plants, animals, insects, killer weather, etc), so the cooperative-pair aspect, say of two parents raising two children each, is advanced.
Thus as your species evolves and grows in intelligence, childhood grows longer, from months (when it was primitive) to many years, and this puts pressure on the pair to stay together. Evolution solves this for them the same way it solved it for humans; with love and pleasure centers they can mutually stimulate, so oxytocin binds the pair together, and they seek to pleasure each other. That sets up the evolutionary feedback loop needed to develop some physical bundle of nerves connected to their brain's reward centers, likely co-located near the excretory organs (since evolution seems to prefer that real estate), similar to a clitoris. So that when stimulated it increases the flood of brain chemicals that create intense pleasure and feelings of love. It is an emotional bonding organ evolved to keep couples together longer, and increase the chances of their offspring's survival to adulthood.
Just like in humans! We don't need love to get pregnant or father a child, or enjoy the sensations of sex. But love does has a biological basis that goes beyond lust. So why did it evolve? It evolved to keep couples together until their children were independent. That isn't 100% successful, but like all evolutionary elements it doesn't have to be, it just needs to increase the odds of success, and it does that much.
Pair-bonding for your species can do the same. But like us, the bond likely has a physical (neurochemical) basis and the bond is reinforced by regular rewards, and this must operate evolutionarily early, before there is much intellect or cognition, while the ancestral species is driven by instinct, emotion and sensation. This is why the bond must be physical with rewarding sensations involved, and the more rewarding those sensations, the stronger the emotional bond.
P.S. I should also add, that if the species is intelligent, then despite the external womb (or "cocoon") used for child development; both instinct and intelligence would evolve to protect this cocoon from predators (making pair bonding even more important; so the cocoon isn't left unguarded in order to search for food). I'd even expect primitive animals using this approach to build a structure around the cocoon to protect it. Birds don't build a nest to keep their eggs high up in a tree for nuthin'! Upon "birth" of the child I'd expect adoption, protection, feeding and education out of parental love.